Mapping the Knowledge Covered by LibraryClassiﬁcation Systems

Chaim Zins
Knowledge Mapping Research, Jerusalem, Israel and Visiting Professor at the Information
Science Post-Graduate Program, Faculdade de Filosoﬁa e Ciências, UNESP – Univ Estadual Paulista.
Marília, Sao Paulo, Brazil.
Plácida L.V.A.C. Santos
Professor at the Information Science Post-Graduate Program, Faculdade de Filosoﬁa e Ciências,
UNESP – Univ Estadual Paulista, Marília, Sao Paulo, Brazil.

This study explores, in 3 steps, how the 3 main libraryclassiﬁcation systems, the Library of Congress Classiﬁcation, the Dewey Decimal Classiﬁcation, and the
Universal Decimal Classiﬁcation, cover human knowledge. First, we mapped the knowledge covered by the
3 systems. We used the “10 Pillars of Knowledge: Mapof Human Knowledge,” which comprises 10 pillars, as
an evaluative model. We mapped all the subject-basedclasses and subclasses that are part of the ﬁrst 2 levels of the 3 hierarchical structures. Then, we zoomed into
each of the 10 pillars and analyzed how the three systems
cover the 10 knowledge domains. Finally, we focusedon the 3 library systems. Based on the way each oneof them covers the 10 knowledge domains, it is evident
that they failed to adequately and systematically present
contemporary human knowledge. They are unsystematicand biased, and, at the top 2 levels of the hierarchicalstructures, they are incomplete.

Introduction
Human knowledge is growing as we conquer new horizons. New ﬁelds emerge as we conceive innovative ideas,
improve our scientiﬁc methods, and invent new technologies.
As a result of this dynamic progress, old books are revised andnew books are written. Our libraries preserve and accumulateknowledge.
The concept of “human knowledge” has two distinct yet
interrelated meanings. One refers to the subjective domain,
and the other refers to the universal domain. “Knowledge”
Received September 25, 2010; revised November 16, 2010; accepted
December 10, 2010
© 2011 ASIS&T • Published online 1 March 2011 in Wiley Online Library(wileyonlinelibrary.com). DOI: 10.1002/asi.21481

in the subjective domain stands for thoughts in the mindof the individual knower—thoughts that can be characterized as justiﬁed true beliefs. “Knowledge” in the universal
domain stands for the accumulated and collective discoveries and thoughts of mankind throughout history—discoveries
and thoughts that have been represented, recorded, anddocumented in textual documents (Zins, 2007). Generally
speaking, human knowledge in the universal domain can becharacterized as the whole collection of textual documents
stored in our libraries. This refers to all types of libraries (i.e.,
traditional and digital, public and private) and all types of
media (i.e., published and digital, visual and vocal). In
this article, we focus on knowledge and knowledge structuresin the universal domain.
The overwhelming quantity of knowledge requires structuring. Knowledge structuring is necessary for meeting two
essential challenges: facilitating an efﬁcient retrieval of thestored contents by providing logical access points, and facilitating a better understanding of the structure of the knowledge
domain and the logical relations among its main parts.
Cognitive maps are essential for learning and using
knowledge (Zins, 2004). The published knowledge maps,
structures, and models to which we are exposed affect our
cognitive maps and, thus, shape the way we perceive theworld and act in it (Zins, 2004, 2006, 2007). For this very
reason, we expect that the knowledge maps that we see inlibraries, museums, books, and Web sites are comprehensive
and systematic.
We are surrounded by numerous published knowledge
maps, structures, and models. We encounter them in libraryclassiﬁcation systems, encyclopedias, Internet directories,
textbooks, and the like. In fact, any introductory book of any
ﬁeld of knowledge presents in its table of contents a knowledge map of the relevant ﬁeld. Tables of contents reﬂect the

JOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, 62(5):877–901, 2011

authors’ maps of the ﬁelds, and they help to shape the readers’cognitive maps.
Throughout history scholars have tried to structure humanknowledge (see, for example, Descartes, Bacon, Locke,
and Leibniz, in Burke, 2000). Among the recent models
is “10 Pillars of Knowledge: Map of Human Knowledge,”
which is a systematic and comprehensive map of contemporary human knowledge (Zins, 2008, 2009), and was used inthis study as the evaluative model.
In the realm of academic and public libraries, there arethree main classiﬁcation systems: the Library of Congress
Classiﬁcation (LCC), the Dewey Decimal Classiﬁcation(DDC), and the Universal Decimal Classiﬁcation (UDC).
Do these library classiﬁcation systems, which are utilized
in tens of thousands of libraries worldwide, adequately andsystematically cover contemporary human knowledge?
Traditional and digital informational environments
include knowledge structured in formats that go beyond thestructures implemented by the three systems. This is the raison d’être for this comparative study, which evaluates andcompares the three main classiﬁcation tools adopted bylibraries and the 10 Pillars of Knowledge, which reﬂects
the way we, the researchers, conceive the structure ofcontemporary human knowledge.
Methodology
The study comprised the following three steps. First, we
mapped the knowledge covered by the three main systems,
LCC, DDC, and UDC. We used the 10 Pillars of Knowledge
tree as an evaluative model. We mapped all the subject-basedclasses and subclasses that are part of the ﬁrst two levels of
the LCC, DDC, and UDC hierarchical structures, for a totalof 41 classes and 386 subclasses: 21 LCC main classes (1stlevel) and 216 LCC main subclasses (2nd level); 10 DDC
main classes and 100 DDC main subclasses; and 10 UDC
main classes and 70 UDC main subclasses. To be precise, weplaced all 41 classes and 386 subclasses of LCC, DDC, andUDC (listed in the Appendix) in the relevant categories of the
10 Pillar hierarchical model.
Generally, we focused on the ﬁrst two levels of the hierarchical structures of LCC, DDC, and UDC. However, in a few
cases, we found it necessary to relate also to the third levelof the hierarchical structure, for example, LCC’s BF and BL
subclasses.
We focus on subject-based classes in this study. We left
out other types of classes that are not associated with speciﬁc
subjects. For example, we left out reference-based classes(e.g., Dewey classes 010 bibliographies, 030 encyclopedias
and books of facts, 050 magazines, journals, and serials, 080
quotations, and 090 manuscripts and rare books) and object
based classes (e.g., Dewey classes 060 associations, organizations, and museums. Note, however, that class 060 is also
associated with the ﬁeld of museology).
For the raw material, we used the September 20th 2008
versions that appeared on the ofﬁcial Web sites of thethree afﬁliated bodies: the Library of Congress Classiﬁcation
878

outline from the Library of Congress (www.loc.gov/catdir/
cpso/lcco); the Dewey Decimal Classiﬁcation summaries
from the Online Computer Library Center (OCLC; http://
www.oclc.org/ dewey/resources/summaries/default.htm); andthe outline of UDC from the Universal Decimal Classiﬁcation(www. udcc.org/outline/outline.htm).
Then, based on the mapping, we zoomed into the 10 pillars
and analyzed how each of the three systems covers the 10
knowledge domains. Finally, we focused on the three librarysystems. Based on the way each one of them covers the 10
knowledge domains, we formulated grounded conclusions on
its overall representation of human knowledge.
Evaluative Model: 10 Pillars of Knowledge
The 10 Pillars of Knowledge tree was used as an evaluativemodel and established the groundwork for the comparative
mapping study. The 10 Pillars of Knowledge is a hierarchicalknowledge tree. The map has different editions and different levels of abstraction. The edition we used for the study
was published in May 2008 (Zins, 2008, 2009; http://www.
success.co.il/knowledge/map/map/html) and comprises 10
main parts, or pillars, which are the ﬁrst-level categories of thehierarchical structure (1st level). The 10 main categories arerespectively divided into 32 main subcategories (2nd level).
The 32 categories are respectively divided into 30 subcategories (3rd level categories). One of them (category 7.3.1) isfurther divided into four subcategories, which form the fourthlevel of the hierarchy (4th level). The four-level structure
comprises 76 categories and subcategories. The 76 categories
partly overlap, forming 55 unique subject categories. The 55
categories are mutually exclusive and collectively cover thebroad spectrum of human knowledge in the universal domain(see the Discussion and Conclusions section).
The 10 Pillars of Knowledge is a systematic map ofhuman knowledge, which presents, at a glance, the structure of knowledge and the meaningful relations among themain ﬁelds. Human knowledge comprises 10 pillars: foundations, supernatural, matter and energy, space and earth,nonhuman organisms, body and mind, society, thought andart, technology, and history. The pillars are deﬁned as follows:
•
•
•
•
•

Foundations is the study of human knowledge.
Supernatural concerns mysticism and religion.
Matter and energy explores the basics of the physical world.
Space and earth explores our planet and outer space.
Nonhuman organisms explores the nonhuman living world,
or fauna and ﬂora.
• Body and mind is focused on the human body and mind.
• Society deals with the various aspects of human social life.
• Thought and art studies the products of the human intellectand the arts.
• Technology explores the products of human creativity, which
are designed to achieve practical aims.
• History encompasses human history.

The 10 pillars are organized into four groups, which
explore four general phenomena: knowledge (pillar 1),

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supernatural (pillar 2), universe (pillars 3–5), and humans(pillars 6–10). From cultural and religious perspectives, nonhuman organisms (pillar 5) and body and mind (pillar 6)
belong to different phenomena. Nonhuman organisms is partof the universe, while body and mind is part of humanity.
However, from a scientiﬁc perspective, nonhuman organisms
and body and mind are interrelated; they are part of the samegeneral phenomenon, the living world.
Every pillar comprises relevant categories. Every category presents the relevant ﬁelds. For example, matter andenergy comprises three main categories: theory, principles,and substances. The theory category comprises two ﬁelds:
philosophy of physics and philosophy of space and time.
The principles category presents physics, and the substances
category presents chemistry. The distinction between categories of the map and ﬁelds of knowledge is essential.
Human knowledge follows a theory-embodiment structure, implemented within the map level, the pillar level, andthe ﬁeld level. At the map level, pillar 1 is the “theory”
part of human knowledge and pillars 2 through 10 are the“embodiment” part. Pillar 1 includes the meta-knowledge(i.e., knowledge about knowledge), or rather the “theory” ofhuman knowledge. Pillars 2-10 embody our knowledge of thesupernatural, the universe, and human phenomena, which are
the center of human exploration.
At the pillar level, the ﬁrst category, theory, is the“theoretical” part of the pillar, which presents ﬁelds that
TABLE 1.

focus on the theoretical aspects of the explored phenomena (e.g., philosophy of knowledge, philosophy of science).
The other categories embody our knowledge of the exploredphenomena. All the pillars, except pillar 8, share the theoryembodiment structure. Pillar 8, thought and art, is divided into
three sections: thought, literature, and the arts (nonliteraryarts) and each one has its own theory-embodiment structure.
At the ﬁeld level, the “theory” section is implemented
in the theory of the ﬁeld (e.g., philosophy of medicine ispart of the “theory” section of medicine). The other sections embody our knowledge of the relevant phenomena.
In the example of medicine, these include internal medicine,
pediatrics, surgery, and the like.
10 Knowledge Domains
We focus on the 10 knowledge domains and analyze how
they are covered by the three systems.
Foundations
The meta-knowledge of human knowledge is represented
in pillar 1, foundations, which is divided into four main categories: theory (1.1), context (1.2), methodology (1.3), andmediation (1.4). The three classiﬁcation systems cover themetaknowledge domain. Table 1 maps the knowledge covered by the main classes of LCC, DDC, and UDC. Table 2

Foundations of knowledge (Pillar 1) at the main classes.
Foundations
10 Pillars

Categories

Fields1.1. Theory

Philosophy of knowledge
Philosophy of science
History of science
Sociology of knowledge
Methodology of science
Information science
Museology
Scientometrics

1.2. Context
1.3. Methodology
1.4. Mediation

TABLE 2.

LCC

DDC

UDC

ClassesClassesClasses

B000; 100

0; 1

A; Q

500

A; C; Z

000

0Foundations of knowledge (Pillar 1) at the main subclasses.
Foundations
10 Pillars

Categories

Fields1.1. Theory

Philosophy of knowledge
Philosophy of science
History of science
Sociology of knowledge
Methodology of science
Information science
Museology
Scientometrics

1.2. Context
1.3. Methodology
1.4. Mediation

LCC

DDC

UDC

ClassesClassesClasses

BD000; 12000; 16

AZ; Q

509

AM; CD; Z

020; 060

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02; 06879

presents the speciﬁc subclasses at the second level of eachclassiﬁcation.
Theory (1.1) is focused on the philosophical perspectivesof knowledge and includes philosophy of knowledge (epistemology), and philosophy of science. Theory is covered by
LCC (BD), DDC (000; 120) and UDC (00; 16). Context(1.2) is focused on the historical and sociological perspectivesof knowledge and includes history of science and sociology ofknowledge. Context is covered by LCC (AZ; Q), and partially by DDC (509 history of science). Note, however, thatsociology of knowledge is covered by DDC at a lower levelof the hierarchical structure by the 306.42 subclass. Context
is not covered by UDC. Methodology (1.3) is focused on
the methodological perspectives of knowledge and includes
one ﬁeld, methodology of science, which covers researchmethodologies in general. It refers to, for example, a general
study on qualitative research. Methodology is not covered
by LCC, DDC, and UDC. Note, however, that in the DDC,
for example, all ﬁelds have methodology sections that are
represented by notation 01 from Table 1. Mediation (1.4)
is focused on the mediating perspectives of knowledge andincludes information science, museology, and scientometrics.
Mediation is covered by LCC (AM; CD; Z), DDC (020; 060)
and UDC (02; 06). Apparently, none of the three systems
comprehensively covers the metaknowledge perspectives ofhuman knowledge.
Supernatural
The supernatural phenomena are represented in pillar 2,
supernatural, which is divided into three main categories:

TABLE 3.

theory (2.1), mysticism (2.2), and religions (2.3). The threeclassiﬁcation systems cover the supernatural phenomena
knowledge domain. Table 3 maps the knowledge covered by
the main classes of LCC, DDC, and UDC. Table 4 presents the
speciﬁc subclasses at the second level of each classiﬁcation.
Theory (2.1) focuses on the philosophical and theoretical perspectives of the supernatural phenomena, including
mysticism and religion, and includes religious studies, philosophy of religion, sociology of religion, and the like. Theory
is covered by LCC (BL), DDC (210), and UDC (2).
Mysticism (2.2) includes a generic ﬁeld, mysticism, which
explores all kinds of mystic phenomena that are not exclusively related to speciﬁc religions. Religion-based mysticism,such as Kabbalah, which is part of the Jewish mysticism,is studied within the context of the relevant religion. The
category is covered only by LCC (Parapsychology (BF10011389), Occult sciences (BF1404-2055)), and DDC (Parapsychology and occultism (130)). In both systems, the mysticalphenomena are represented in third-level classes, as subclasses of psychology and philosophy (mutatis mutandis),rather than religion. This is strange because both systems
assign parapsychology and occultism mainly to religious
phenomena. Evidently, the coverage of mysticism by LCC
and DDC is not systematic.
Religions (2.3) is focused on the world religions, which
are classiﬁed into ﬁve classes: ancient, monotheism, asian,modern, and ethnic. The three classiﬁcation systems cover
the various religions. However, the scope and structure of thecoverage are different. Ancient religions (2.3.1) are represented by LCC in various subclasses of religions, mythology,
rationalism (BL; e.g., the myth, comparative mythology

Supernatural: Mysticism and religion (Pillar 2) at the main classes.
Supernatural
10 Pillars

LCC

DDC

UDC

ClassesClassesClasses2

Categories

Fields2.1. Theory

Religious studies

B

200

2.2. Mysticism

Mysticism

B

100

Egyptian mythology
Greek mythology

B

200

2

2.3.2. Monotheism

Judaism
Christianity
Islam

B

200

2

2.3.3. Asian

Buddhism
Jainism
Sikhism
Confucianism
TaoismShintoBahaism
Zoroastrianism

B

200

2

2.3.4. Modern

Scientology

200

2

2.3.5. Ethnic

Shamanism
Voodoo200

22.3. Religions
2.3.1. Ancient

880

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TABLE 4.

Supernatural: Mysticism and religion (Pillar 2) at the main subclasses.
Supernatural
10 Pillars

Categories

Fields

LCC

DDC

UDC

ClassesClassesClasses

2.1. Theory

Religious studies

BL

210

2.2. Mysticism

Mysticism

BF

130

Egyptian mythology
Greek mythology

BL

290

21; 252.3.2. Monotheism

Judaism
Christianity
Islam

BM; BP; BR; BS;
BT; BV; BX

220; 230; 240; 250;
260; 270; 280; 290

26; 27; 28

2.3.3. Asian

Buddhism
Jainism
Sikhism
Confucianism
TaoismShintoBahaism
Zoroastrianism

BL; BP; BQ

290

22; 23; 24

2.3.4. Modern

Scientology

290

29

2.3.5. Ethnic

Shamanism
Voodoo290

252.3. Religions
2.3.1. Ancient[BL300-325]). DDC represents the category in several subclasses of other religions (290; e.g., Greek and Roman
religion [292]). UDC represents ancient religions in two subclasses: prehistoric and primitive religions (21) and religionsof antiquity and minor cults and religions (25).
Monotheist religions, namely, Judaism, Christianity, andIslam (2.3.2), are covered by LCC, DDC, and UDC. LCC
covers Judaism, Christianity, and Islam in seven subclasses:
Judaism (BM); Islam, Bahism, and theosophy (BP); Christianity (BR); The Bible (BS); doctrinal theology (BT);practical theology (BV); and Christian denominations (BX).
The seven classes are not mutually exclusive. The three lastclasses, doctrinal theology (BT), practical theology (BV),
and Christian denominations (BX), should be subclasses ofChristianity (BR), rather than at the same level of the hierarchical structure. The classes differ by the types of objects they
represent. Three classes–Judaism (BM), Christianity (BR),and Islam, Bahism, theosophy (BP)–represent religions. Notethat BM and BR represent speciﬁc religions while BP represents several religions. One class, BS, represents scriptures.
Two classes, BT and BV, represent religious ideologies (i.e.,thoughts), and one class, BX, represents religious groups(i.e., people). Religions, scriptures, thoughts, and people
belong to different types of objects. Evidently, the representation of the monotheist religions by LCC is not systematicand Christianity biased.
The way DDC covers the monotheist religions is evenmore problematic. DDC dedicates eight subclasses to thethree religions: Bible (220); Christianity and Christian theology (230); Christian practice and observance (240); Christian pastoral practice and religious orders (250); Christian2organization, social work, and worship (260); history of
Christianity (270); Christian denominations (280); and otherreligions (290). Six classes are exclusively dedicated to Christianity, and one is dedicated to the Bible, which is common
to both Judaism and Christianity (i.e., Bible [220]). Only one
class, other religions (290), represents Judaism and Islam in
addition to all the other religions. Evidently, this knowledge
representation is incomplete, unsystematic, and Christianity
biased.
UDC representation of the monotheism category is balanced. UDC dedicates three unique classes—a class for eachreligion: Judaism (26), Christianity (27), and Islam (28).
However, the coverage of the three knowledge domains is
incomplete and, therefore, not systematic.
Asian religions (2.3.3) are covered by the three systems.
LCC represents the Asian religions in three classes: religions, mythology, and rationalism (BL); Islam, Bahism,
theosophy (BP); and Buddhism (BQ). The knowledge covered in the three classes is incomplete and not systematic.
For example, Hinduism and Jainism are treated within the
broader subclass history and principles of religions (BL6602680). This class can be used as an umbrella name for all
religions. However, several religions including Hinduismand Jainism are exclusively represented in this class, whileother religions (e.g., Buddhism) are represented in separate
classes.
DDC relates to all the religions, except Christianity, in thevague category named “other religions” (290). Zooming into
the other religions category shows that knowledge representation of Asian religions is incomplete at the top two levelsof the hierarchical structure.

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UDC relates to the Asian religions in three classes: religions of the Far East (22), religions of the Indian subcontinent(23), and Buddhism (24). Apparently, the scope of the coverage is comprehensive, because all the Asian religions areincluded under the 22 class, which is an umbrella class for
all the Asian religions. However, for this very reason, thestructure is not systematic. Classes 23 and 24 should be subclasses of class 22, rather than belong to the same level of thehierarchical structure.
Modern religions and ethnic religions are not covered by
LCC in the ﬁrst two levels of the hierarchical classiﬁcation.
DDC relates to modern and ethnic religions in one subclass (290), under the strange title “religions not provided forelsewhere” (299). Apparently, this is incomplete and unsystematic coverage. UDC relates to modern religions in themodern spiritual movements (29) class. Ethnic religions arecovered in UDC in the minor cults and religions (25), but
the coverage is incomplete.
To summarize, the three systems cover the supernatural
knowledge domain. LCC and DDC coverage is incomplete,unsystematic, and Christianity biased. UDC coverage is morebalanced, but it is still too incomplete and not systematic. The
unsystematic character of the UDC structure is also apparent
at the subclasses level. The religion/theology (2) class comprises nine subclasses: ﬁve relate to groups of religions (21,22, 23, 25, and 29), while four relate to speciﬁc religions (24,
26, 27, and 28).
Matter and Energy
The physical universe is represented in pillars 3 and 4.
Pillar 3 focuses on the basics of the physical universe and is
TABLE 5.

divided into three categories: theory (3.1), principles (3.2),
and substances (3.3). The three classiﬁcation systems cover
the basics of the physical universe. Table 5 maps the knowledge covered by the main classes of LCC, DDC, and UDC.
Table 6 presents the speciﬁc subclasses at the second level ofeach classiﬁcation.
Theory (3.1) represents philosophy of physics and philosophy of space and time. The category is covered in LCC by
the science general (Q1-295) subclass. In DDC, it is covered by the philosophy and theory (501) subclass. DDC
covers the theory category in the physics (53) subclass,as part of physics, rather than an independent class that
relates to the entire physical phenomena. Despite this critique, we conclude that the three systems comprehensively
and systematically cover the theory category.
Principles (3.2) includes physics. LCC relates to physics
in the physics (QC1-999) class. Note that the last two subclasses of physics (QC1-999), geomagnetism (QC811-849)
and meteorology and climatology (QC851-999), belong toearth sciences rather than to physics. However, these inaccuracies can be attributed to a lack of better classes in the LCC
structure rather than to a misconception of physics. DDC
represents physics in the physics (530) subclasses. UDC represents physics in the physics (53) subclasses. Generally, theknowledge coverage of physics by LCC, DDC, and UDC
seems to be comprehensive and systematic.
Substances (3.3) represents chemistry. LCC represents
chemistry in the chemistry (QD1-999) class. The last subclass of chemistry, crystallography (QD901-999), is not partof chemistry. This presents an interesting situation. On one
hand, the coverage of chemistry by LCC is not systematic(because crystallography is not a subﬁeld of chemistry), but

Matter and energy (Pillar 3) at the main classes.
Matter & Energy
10 Pillars

LCC

DDC

UDC

ClassesClassesClassesCategories

Fields

3.1. Theory

Philosophy of physics
Philosophy of space and time

Q

500

5

3.2. Principles

PhysicsQ

500

53.3. Substances

Chemistry

Q

500

5

LCC

DDC

UDC

ClassesClassesClasses500

53

TABLE 6.

Matter and energy (Pillar 3) at the main subclasses.
Matter and energy
10 Pillars

Categories

Fields

3.1. Theory

Philosophy of physics
Philosophy of space and time

3.2. Principles

Physics

QC

530

53

3.3. Substances

Chemistry

QD

540

54

882

Q

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on the other hand, the ﬁeld of crystallography should beplaced here in the substances category. Therefore, if we ignore
this critique, then the coverage of the substances category by
LCC is comprehensive and systematic.
This seems to be the case with DDC and UDC as well.
Both classiﬁcation schemes list crystallography and mineralogy among the chemistry subclasses. In DDC, the chemistry
and allied sciences (540-549) classes include crystallography(548) and mineralogy (549). In UDC, the chemistry, crystallography, and mineralogy (54: 542-549) class includes two
subclasses, crystallography (548) and mineralogy (549), thatare not part of chemistry. However, it seems that the editorsof both systems are aware of the distinction among chemistry, crystallography, and mineralogy. The inclusion of thethree ﬁelds in the same class seems to be related to the limitations of the decimal principle rather than to misconceptions
regarding the ﬁelds. Consequently, we ignore this critiqueand characterize the coverage of the substances category by
DDC and UDC as being comprehensive and systematic.
To summarize, the basics of the physical universe arecovered by LCC, DDC, and UDC. The coverage is comprehensive and systematic. Still, the editors of the threesystems need to separate among chemistry, crystallography,
and mineralogy while revising their systems.
TABLE 7.

Space and Earth
The outer space and the earth are represented in pillar
4, which is divided into three main categories: theory (4.1),
space (4.2), and earth (4.3). The three classiﬁcation systems
cover the space and earth phenomena. Table 7 maps theknowledge covered by the main classes of LCC, DDC, andUDC. Table 8 presents the speciﬁc subclasses at the second
level of each classiﬁcation.
Theory (4.1) represents cosmological theory, or scientiﬁccosmology, which is the study of the universe as a uniﬁed
whole and its origin. It is a ﬁeld of knowledge aiming at
providing a scientiﬁc based explanation of the nature of thephysical universe and its origin. LCC and DDC cover the 4.1
category. LCC uses the astronomy (QB349-421 and QB980991) subclass. UDC uses the astronomy (521 and 524.8)
subclass.
Space (4.2) includes astronomy. LCC (QB), DDC (520),
and UDC (52) cover the category. Note that the three astronomy subclasses (QB, 520, and 52) need to be revised because
they include subjects that belong to earth sciences rather
than astronomy. LCC includes geodesy, which is a subﬁeld of geology. DDC includes mathematical geography and“earth (astronomical geography).” UDC includes geodesy,
cartography, and aerial photography.

Space and Earth (Pillar 4) at the main classes.
Space and earth
10 Pillars

Categories

Fields

LCC

DDC

UDC

ClassesClassesClasses

4.1. Theory

Cosmological theoryQ

4.2. Space

Astronomy

Q

500

5

Physical geography
Geology
Soil sciences

G; Q

500

5

Agriculture
Environmental sciences
Natural hazards

S

600

5; 6

LCC

DDC

UDC

ClassesClassesClasses

4.3. Earth
4.3.1. Surface and substance

4.3.2. Interrelations

TABLE 8.

5

Space and Earth (Pillar 4) at the main subclasses.
Space and earth
10 Pillars

Categories

Fields

4.1. Theory

Cosmological theoryQB

4.2. Space

Astronomy

QB

520

52

Physical geography
Geology
Soil sciences

G; GA;
GB; GC;
QE

550

52; 54; 55

Agriculture
Environmental sciences
Natural hazards

GE; S;
SB; SD;
SF; SH630

50; 634.3. Earth
4.3.1. Surface and substance

4.3.2. Interrelations

52

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Earth (4.3) is divided into two subcategories, surface andsubstance (4.3.1), and interrelations (4.3.2). Surface and substance is focused on exploring the surface and substance ofthe earth. The category includes physical geography, geology, and soil sciences. The category is covered by the threesystems. LCC represents the category in ﬁve subclasses:
geography (general; G); mathematical geography and cartography (GA); physical geography (GB); oceanography (GC);and geology (QE). The structure does not reﬂect the relationship among these ﬁelds. Mathematical geography andoceanography are subﬁelds of physical geography.
DDC represents the category in the earth sciences andgeology (550) subclass. The title and the structure of the subclass are confusing and need to be revised because geology
is part of earth sciences.
UDC represents the 4.3.1 category in three subclasses:
astronomy, astrophysics, space research, geodesy (52); chemistry, crystallography, mineralogy (54); and earth sciences,geology, meteorology (55). The structure is unsystematic anddoes not reﬂect the relationship among these ﬁelds. “Earthsciences” is an umbrella name for all the sciences that explore
the earth. Earth sciences include geography (which includes
meteorology) and geology (which includes crystallography,
geodesy, and mineralogy). It seems that in UDC (as well as in
DDC), “earth sciences” is equivalent to “geography.” However, replacing “earth sciences” with “geography” will not
resolve the confusion.
Interrelations (4.3.2) is focused on the relations between
the earth and humans and comprises three ﬁelds: agriculture,environmental sciences, and natural hazards. These ﬁelds
are interdisciplinary and relate to several pillars. Agriculture, for example, explores the cultivation of the earth andits main subﬁelds are as follows: horticulture (the study ofplant cultivation); forestry (the study of managing forests andtree plantations); animal husbandry (the study of breeding
and raising livestock); aquaculture (the study of farming of
freshwater organisms); and ﬁshery (the study of raising andharvesting ﬁshes). Modern agriculture is an interdisciplinaryﬁeld, which embodies the use of natural resources (soil andwater) for improving biological-based products (for example, meat, fruits, and vegetables) by human involvement andtechnologies (e.g., genetic engineering, pesticides, and agricultural machinery). Therefore, the following three pillars
can represent agriculture: space and earth (pillar 4), nonhuman organisms (pillar 5), and technology (pillar 9). To
avoid confusion, agriculture, environmental sciences, andnatural hazards are listed only here.
Natural hazards explores the efﬁcient ways to control
the devastating powers of nature and facing natural catastrophes. It is an interdisciplinary ﬁeld. The main hazards
are as follows: geological hazards (avalanches, earthquakes,
landslides and mudﬂows, sinkholes, and volcanic eruptions); hydrological hazards (ﬂoods and tsunamis); climatic and atmospheric hazards (blizzards/winter storms);
droughts and hailstorms (frozen rain); heat waves andcyclonic storms (hurricanes); ice storms; tornados; andwildﬁres.
884

LCC covers the category in environmental sciences (GE),agriculture (general) (S), plant culture (SB), forestry (SD),animal culture (SF), and aquaculture, ﬁsheries, angling (SH).
DDC covers the interrelations category in the agriculture(630). UDC covers the interrelations category in the environmental sciences: conservation of natural resources, threats tothe environment, and protection (502/504); and agriculture
and related sciences and techniques, forestry, farming, andwildlife exploitation (63). It seems that LCC, DDC, and UDC
adequately cover agriculture and environmental sciences, but
the coverage of natural hazards is incomplete.
To summarize, the coverage of the earth and spaceknowledge domain by the three systems is incomplete andunsystematic.

The Living WorldThe living world is represented in pillars 5 and 6. The nonhuman living world is represented in pillar 5, which is divided
into three categories: theory (5.1), basic sciences (5.2), andhealth and well-being (5.3). The three classiﬁcation systems
cover the nonhuman living world. Table 9 maps the knowledge covered by the main classes of LCC, DDC, and UDC.
Table 10 presents the speciﬁc subclasses at the second levelof each classiﬁcation.
Theory (5.1) is focused on the philosophical and ethicalperspectives, which comprises philosophy of biology andbioethics. The category is covered in LCC by the biology(general; QH) subclass. In UDC, it is covered by the general and theoretical biology (573) subclass. DDC covers thecategory in the 570.1 subclass.
Basic sciences (5.2) is focused on biology and its various subﬁelds, except human biology. LCC represents biology
in the natural history-biology (QH), botany (QK), zoology(QL), physiology (QP), and microbiology (QR) subclasses.
The coverage of biology in these LCC’s classes is incomplete and unsystematic. Main subﬁelds of biology are missing(e.g., developmental biology). Evidently, the structure of thebiological sciences is not systematic. Botany, zoology, physiology, and microbiology are subclass of biology, Therefore,
subclasses QK, QL, QP, and QR should be subclasses of QH
rather than belonging to the same level of the hierarchicalclassiﬁcation as subclasses of Q. Furthermore, the physiology (QP) class includes two unrelated subclasses, animalbiochemistry (QP501-801) and experimental pharmacology(QP901-981). Clearly, biochemistry and pharmacology are
not subﬁelds of physiology. Physiology and biochemistry are
subﬁelds of biology, while pharmacology is an independentﬁeld of knowledge. To summarize, the coverage of the basic
sciences category by LCC is incomplete and unsystematic.
Both DDC’s and UDC’s representations of the biologicalsciences are similar. Both systems have four main subclasses.
DDC represents the following subclasses: biological sciencesin fossils and prehistoric life (560); life sciences and biology(570); plants (botany; 580); and animals (zoology; 590). UDC
represents the following subclasses: biological sciences in

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TABLE 9.

Non-human organisms (Pillar 5) at the main classes.
Non-Human Organism
10 Pillars

LCC

DDC

UDC

classesclassesclassesCategories

Fields

5.1. Theory

Philosophy of Biology
Bioethics

Q

500

5

5.2. Basic Sciences

Biology

Q; S

500

5

5.3. Health & Wellbeing

Veterinary Medicine

S

TABLE 10.

Non-human organisms (Pillar 5) at the main subclasses.
Non-Human Organism
10 Pillars

LCC

DDC

UDC

classesclassesclassesCategories

Fields

5.1. Theory

Philosophy of Biology
Bioethics

QH

570

57

5.2. Basic Sciences

Biology

QH; QK; QL; QP; QR;

560; 570; 580; 590

56; 57; 58; 59

5.3. Health & Wellbeing

Veterinary Medicine

SFpalaeontology (56); biological sciences in general (57: 573–
579); botany (58); and zoology (59). Both representations
are neither comprehensive nor systematic, for the same reasons. First, the four-class structure–paleontology, biology,
plants (botany), and animals (zoology)–is not systematic.
The four ﬁelds do not belong to the same level of the hierarchy. These are not four distinct ﬁelds of the same level.
Paleontology, botany, and zoology are subﬁelds of biology.
The structures of DDC and UDC are misleading. Lay people can easily misunderstand the logical relations among thefour concepts. Second, both classiﬁcations do not represent
main biological sciences. For example, UDC and DDC do
not refer to the anatomy of nonhuman organisms. Evidently,
DCC and UDC fail to comprehensively and systematicallycover contemporary scientiﬁc knowledge in the biologicalsciences.
Health and well-being (5.3) represents veterinary
medicine. LCC represents veterinary medicine in the veterinary medicine (SF600-1100) class, which is a subclassof agriculture (SF). Evidently, veterinary medicine is nota subﬁeld of agriculture; therefore, LCC’s representationof the health and well-being category is not systematic.
Surprisingly, DDC and UDC do not represent the ﬁeld of veterinary medicine in the ﬁrst three levels of their hierarchicalstructures.
To summarize, pillar 5, which represents our knowledge
on the nonhuman living world, is covered by LCC, DDC,
and UDC. Regrettably, the three classiﬁcation systems failto adequately cover the knowledge domain. The three representations of the knowledge domain are incomplete andunsystematic.

Body and Mind
The human body (chemo-physical) and mind is represented in pillar 6, body and mind, which is divided into
three categories: theory (6.1), basic sciences (6.2), and healthand well-being (6.3). The three classiﬁcation systems cover
the phenomena. Table 11 maps the knowledge coveredby the main classes of LCC, DDC, and UDC. Table 12
presents the speciﬁc subclasses at the second level of eachclassiﬁcation.
Theory (6.1) is focused on the philosophical and ethical perspectives of the human body and mind phenomena,
which comprises philosophy of life, philosophy of mind, andbioethics. The category is covered in LCC by the ontology(BD300-450) subclass. Note that subclass R723-726 (medical philosophy and medical ethics) that is focused on thephilosophical perspectives of medicine covers category 6.3.1
rather that category 6.1. UDC uses philosophy of mind (13)subclass. DDC does not cover the 6.1 category.
Basic sciences (6.2) is focused on the biological and psychological aspects of the human body and mind diversiﬁed
phenomena. The category represents human biology, psychology, neuroscience, and cognitive science. LCC covers thecategory in the psychology (BF), biology (general; QH301705.5), human anatomy (QM), and, partially, in physiology(QP1-495) classes. DDC covers the category in the psychology (150), life sciences and biology (570), human anatomy,
cytology, and histology (611), and human physiology (612)subclasses, which are subclasses of medicine and health(610). UDC covers the basic sciences category in psychology (159.9), biological sciences (57), and medical sciences(61) subclasses. Note that psychology has a strange number

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TABLE 11.

Body and mind (Pillar 6) at the main classes.
Body and mind
10 Pillars

LCC

DDC

UDC

ClassesClassesClassesCategories

Fields

6.1. Theory

Philosophy of life
Philosophy of mind
Bioethics

R

6.2. Basic sciences

Human biology
Psychology
Neuroscience
Cognitive science

B; Q

100; 500; 600

1; 5; 6

Medicine
Dentistry

R

600

6

6.3.2. Paramedical studies

Audiology
Clinical psychology
MidwiferyNursingNutrition
Occupational therapy
Optometry
Physical therapy
Public health
Speech therapy

R

600

6

6.3.3. Complementary medicine

Ayurvedic medicine
Chinese medicine
HomeopathyR

6.3. Health and well-being
6.3.1. Medical sciences

TABLE 12.

1

Non-human organisms (Pillar 6) at the main subclasses.
Body and mind
10 Pillars

LCC

DDC

UDC

ClassesClassesClassesCategories

Fields

6.1. Theory

Philosophy of life
Philosophy of mind
Bioethics

BD

6.2. Basic sciences

Human biology
Psychology
Neuroscience
Cognitive science

BF; QH; QM; QP

150; 570; 610

159.9; 57; 61

Medicine

R; RA; RB; RC; RD;
Dentistry
RL, RM

610
RE; RF; RG; RJ; RK;

61

6.3.2. Paramedical studies

Audiology
Clinical psychology
MidwiferyNursingNutrition
Occupational therapy
Optometry
Physical therapy
Public health
Speech therapy

RE; RM; RS; RT

610

61

6.3.3. Complementary medicine

Ayurvedic medicine
Chinese medicine
Homeopathy

RV; RX; RZ

6.3. Health and well-being
6.3.1. Medical sciences

886

13

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(159.9), rather than 15. To summarize, the coverage of the
6.2 category by the three systems is partial.
Health and well-being (6.3) is focused on human healthand medical sciences. The category comprises three mainsubcategories: medical sciences (6.3.1), paramedical studies (6.3.2), and complementary medicine (6.3.3). Medical
sciences (6.3.1) includes medicine and dentistry. The category is covered by LCC, DDC, and UDC. LCC uses
class R and its subclasses are as follows: R, RA, RB,
RC, RD, RE, RF, RG, RJ, RK, RL, and RM. In comparing the topics covered by LCC with the topics coveredby the National Library of Medicine (NLM; http://www.
nlm.nih.gov/pubs/factsheets/nlmclassif.html) classiﬁcation
system, it becomes clear that many important ﬁelds are missing. DDC covers the category in medicine and health (610)
subclass. UDC covers the category in medical sciences (61)category. Paramedical studies (6.3.2) includes various ﬁelds,such as audiology, clinical psychology, midwifery, nursing,nutrition, occupational therapy, optometry, physical therapy,
public health, speech therapy. LCC covers the category in
RE, RM, RS, and RT subclasses. DDC covers the category
in class 610. UDC covers the category in class 61. Complementary medicine (6.3.3) is covered only by LCC in RV, RX,
and RZ subclasses.
To summarize, LCC, DDC, and UDC cover the humanbody and mind diversiﬁed phenomena, but the coverage isincomplete and unsystematic.
Society
The human society is represented in pillar 7, society,which is divided into four categories: theory (7.1), society
at-large (7.2), domains (7.3), and social groups (7.4). The
three classiﬁcation systems cover the various perspectivesof human social life. Table 13 maps the knowledge covered by the main classes of LCC, DDC, and UDC. Table 14
presents the speciﬁc subclasses at the second level of eachclassiﬁcation.
Theory (7.1) is focused on the philosophical basis of social
life and the social sciences. The category contains two ﬁelds:
philosophy of social sciences and social philosophies. The
category is covered in LCC by the social sciences (general;H) and HX subclasses. DDC covers the category in the social
sciences (301.1) subclass. UDC covers the category in thetheories and methods in social sciences (30) subcategory.
Society at-large (7.2) represents social sciences thatencompasses diversiﬁed social aspects. These integrated
ﬁelds are grouped into two categories: general and areabased. The general category (7.2.1) represents four ﬁelds:sociology, anthropology, human geography, and demography. The category is covered by LCC, DDC, and UDC. LCC
covers the category in 11 subclasses: geography (general; G),
GF, GN, GR, GT, HB, HM, HN, HQ, HS, and HT. DDC covers the category in 300 (300-307), 390, 910 subclasses. UDC
covers the category in 31, 39, and 91.
The area-based category (7.2.2) comprises hundreds ofﬁelds that ﬁt the umbrella name “area studies.” These are

multidisciplinary ﬁelds of research and scholarship relating
to particular geographical areas. Area studies is multidisciplinary, rather than interdisciplinary. It combines naturalsciences (e.g., geography, geology, biology), social sciences(e.g., sociology, anthropology, political science, history), andhumanities (e.g., literature, art, religion) in a uniﬁed academic
framework. The area -based category (7.2.2) is not covered
by LCC, DDC, and UDC.
The domains category (7.3) represents social sciences that
focuses on speciﬁc areas of social life. The category comprises three main subcategories: community (7.3.1), needs
and activities (7.3.2), and management (7.3.3). Community
focuses on the basics of social life. Needs and activities
focuses on human needs (e.g., education, health, security),and human activities (e.g., culture, economics, sport). Management focuses on the management and the administrationof social life.
The community category (7.3.1) explores the basics ofsocial life, which represents four main subcategories: communication (7.3.1.1), contract (7.3.1.2), codes (7.3.1.3), andconduct (7.3.1.4). Communication focuses on the basics ofsocial interaction. Contract focuses on the “social contract”
that underlies the binding power of social structures that control and regulate social life. Codes focuses on the guiding
principles and rules (codes) of human conduct and social
interaction. Conduct focuses on human behaviour in thesocial context.
Communication (7.3.1.1) represents four ﬁelds: semiotics, linguistics, languages (which is subdivided by world
languages), and communication studies. LCC covers the category in the following 13 subclasses: P, PA, PB, PC, PD,
PE, PF, PG, PH, PJ, PK, PL, and PM. DDC covers the category in the following 10 subclasses: 400, 410, 420, 430,
440, 450, 460, 470, 480, and 490. UDC covers the category in 80, 81, and 82 subclasses. The three systems focus
mainly on linguistics and languages, but the coverage ofthousands of natural languages is partial and unsystematic;
DDC, for example, assigns eight subclasses for languages(class. 420-490). The ﬁrst seven are assigned to speciﬁclanguages—English, German, French, Italian, Romanian,
Spanish, Portuguese, Latin, Italic, and Greek—, while theeighth subclass is assigned to all the other languages. Furthermore, the coverage of communication studies is inadequate.
The three systems refer to the technological and the economic
aspects of the communication industry (see class HE [LCC],
380 [DDC], and 654/659), but they do not refer to the social
aspects of communication as a social phenomenon, which
underlies any social and interpersonal interaction. To summarize, the coverage of the 7.3.1.1 category by the threesystems is extensive, but it is not comprehensive and not
systematic.
Contract (7.3.1.2) explores the theory and practice of political systems and the use and abuse of political power. The
name of the category comes from the notion of social contract as the rational basis of national states. The category
represents political science. LCC covers the category in thefollowing 13 subclasses: CD, J, JA, JC, JF, JJ, JK, JL, JN,

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TABLE 13.

Society (Pillar 7) at the main classes.
Society
10 Pillars

LCC

DDC

UDC

ClassesClassesClassesCategories

Fields

7.1. Theory

Phil. of soc. sciences
Social philosophy

H

300

3

Sociology
Anthropology
Human geography
Demography

G; H

300; 900

3; 9

P

400

8

7.2. Society at-large
7.2.1. General

7.2.2. Area-based
7.3. Domains
7.3.1. Community
7.3.1.1. Communication

Area studies(classiﬁed by area)

Semiotics
Linguistics
Languages
Communication studies

7.3.1.2. Contract

Political science

C; J

100; 3003

7.3.1.3. Codes

EthicsLaw

B; K

100; 300

1;3

7.3.1.4. Conduct

Social psychology
Criminology

H

7.3.2. Needs and activities

Cultural studies
Economics
Education
Public health
Recreation
Social work
Sport
Tourism
Urban planning

A; C; G; H; L; S;
T; U; V

300; 600; 700; 900

3; 6; 77.3.3. Management

Management studies

J300; 600

0; 3; 6

Men’s studies
Women’s studies

H

7.4. Social groups
7.4.1. Gender
7.4.2. Age

Youth studies
Gerontology

7.4.3. Ethnicity

Ethnic studies(ethnic subdivision)

7.4.4. Interest

Family studies
Gay and lesbian studies

JQ, JS, JV, and JZ. DDC covers the category in 172 (political
ethics) and 320 subclasses. UDC covers the category in 32
and 35 subclasses. LCC, DDC, and UDC adequately cover
the category.
Codes (7.3.1.3) represents ethics and law. LCC, DDC,
and UDC cover the category. LCC uses the following 16
subclasses: BJ (Ethics); K (Law, general); KB (Religiouslaw) and its subclasses; KBM (Jewish law); KBP (Islamiclaw); KBR (Canon law); KBU (Roman Catholic law); KDKDK (UK and Ireland); KDZ (America. North America); KE(Canada); KF (US); KG (Latin America); KH (South America); KJ-KKZ (Europe); KL-KWX (Asia and Eurasia, Africa,
Paciﬁc Area, and Antarctica); KZ (Law of nations). DDC uses
888

3

3

H

two subclasses, 170 (Ethics) and 340 (Law). UDC uses two
subclasses, 17 (Ethics) and 34 (Law).
We zoom into the law. Apparently, LCC coverage of law
is extensive, but incomplete and unsystematic. LCC assigns
15 subclasses for law. Two subclasses focus on the coreknowledge of the ﬁeld (K, and KZ). Five subclasses focus
on religious law, mainly on Christian, Jewish, and Islamiclaw (KB, KBM, KBP, KBR, and KBU). Eight subclasses(KD-KDK, KDZ, KE, KF, KG, KH, KJ-KKZ, and KL-KWX)
focus on national legal systems. Apparently, DDC coverageof law is extensive, but incomplete and unsystematic. DDC
assigns 10 subsubclasses for law. Nine subclasses focus on
the core knowledge of the ﬁeld (340-348); one subclass is

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TABLE 14.

Society (Pillar 7) at the main subclasses.
Society
10 Pillars

LCC

DDC

UDC

ClassesClassesClassesCategories

Fields

7.1. Theory

Phil. of soc. sciences
Social philosophy

H; HX

301

30

Sociology
Anthropology
Human geography
Demography

G; GF; GN; GR;
GT; HB; HM; HN;
HQ; HS; HT;

300–307; 390; 910

31; 39; 91

Semiotics
Linguistics
Languages
Communication studies

P; PA; PB; PC;
PD; PE; PF; PG;
PH; PJ; PK;
PL; PM

400; 410; 420; 430;
440; 450; 460; 470;
480; 490

80; 81; 82

7.3.1.2. Contract

Political science

CD; J: JA; JC; JF;
JJ; JK; JL; JN; JQ;
JS; JV; JZ

170; 320

32; 357.3.1.3. Codes

EthicsLaw

BJ; K; KB; KBM;
KBP; KBR; KBU;
KD-KDK; KDZ; KE;
KF; KG; KH; KJ-KKZ;
KL-KWX; KZ

170; 340

17; 347.3.1.4. Conduct

Social psychology
Criminology

HV

360

31; 347.3.2. Needs and activities

Cultural studies
Economics
Education
Public health
Recreation
Social work
Sport
Tourism
Urban planning

AS; CJ; GV; HB; HC;
HD; HE; HF; HG; HJ;
HV; L; LA; LB; LC;
LD; LE; LF; LG; LJ;
SH; SK; TS; TX;
U; UA; UB; UC; UD;
UE; UF; UH; V;
VA; VB; VC; VD; VE;
VF; VG; VK

330; 350; 360; 370;
380; 640; 790; 910

33; 36; 37; 64;
65; 71; 79

7.3.3. Management

Management studies

JF; JJ; JK; JL; JN;
JQ; HD; HF; HG

350; 650

00; 35; 65

Men’s studies
Women’s studies

HQ

7.2. Society at-large
7.2.1. General

7.2.2. Area-based

Area studies(classiﬁed by area)

7.3. Domains
7.3.1. Community
7.3.1.1. Communication

7.4. Social groups
7.4.1. Gender
7.4.2. Age

Youth studies
Gerontology

7.4.3. Ethnicity

Ethnic studies(ethnic subdivision)

7.4.4. Interest

Family studies
Gay and lesbianstudies30

HQ

focused on national and area-based legal systems (349). UDC
assigns 10 subsubclasses for law. Nine subclasses focus on
the core knowledge of the ﬁeld (34-347, 349); one subclassis focused on religious law (348).
The ﬁeld of law encompasses the following areas: legal
theory (i.e., the theoretical foundations of the law, including

history of law, philosophy of law, or jurisprudence); sociology of law and economy of law; legal systems (i.e., civil law,common law, and religious law); legal areas (i.e., public law
including constitutional law, administrative law, and criminal law); private law (contract law, tort law, and propertylaw) and international law; legal institutions (the judiciary

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system and the legislature system); legal issues (e.g. humanrights, end of life issues, and copyright issues); national legal
systems (subdivided by countries); and legal professions.
Upon reviewing how each of the three systems covers law,
it is evident that the coverage is extensive. To be speciﬁc,
LCC’s coverage of the core knowledge of law seems to becomprehensive, but it is deﬁnitely unstructured. The coverageof religious law is incomplete and unsystematic. It ignores
Asian and modern religions. The coverage of national andarea-based law seems comprehensive, but it is not systematic
because the attention to North America is not proportional.
Without delving into details, the coverage by DDC and UDC
seems complete and systematic. To summarize, the coverageof the 7.3.1.3 category by the three systems is extensive. However, the cover by LCC is incomplete and unsystematic, while
the cover by DDC and UDC is complete and systematic.
Conduct (7.3.1.4) involves human social behavior. It represents social psychology and criminology. LCC covers thecategory in the HV subclass. DDC covers the category in
the 360 subclass. UDC covers the category in the 31 (316.6[social psychology]) and the 34 (343.9 [criminology]) subclass. Without delving into details, the coverage by the threesystems seems complete and systematic.
The needs and activities category (7.3.2) encompasses
areas of human activity and represents cultural studies, economics, education, public health, recreation, social work,
sport, tourism, urban planning, and the like. The three systems cover the category. LCC covers the category in 41
subclasses: AS, CJ, GV, HB, HC, HD, HE, HF, HG, HJ, HV,
L (education [general]); LA, LB, LC, LD, LE, LF, LG, LJ,
SH (angling); SK (hunting sports); TS (manufactures); TX(home economics); U (military science [general]); UA, UB,
UC, UD, UE, UF, UH, V (naval science [general]); VA, VB,
VC, VD, VE, VF, VG, and VK. DDC uses eight subclasses:
330 (economics); 350 (military science); 360 (social problems and social services); 370 (education); 380 (commerce,
communications and transportation); 640 (home and family
management); 790 (sports, games and entertainment); and910 (travel). UDC uses seven subclasses: 33 (economics); 36(social welfare); 37 (education); 64 (home economics); 65(communication and transport industries. public relations);
71 (urban and rural planning); and 79 (recreation, entertainment, games, sport). Without delving into details, thecoverage of the category by LCC, DDC, and UDC is complete
and systematic.
The management category (7.3.3) is the study of the theory and practice of management and administration of social
activities and organizations. The category includes a genericﬁeld–management studies–that relates to the public (e.g.,
governmental and NGOs) and private (e.g., business) sectors. LCC covers the public sector in six subclasses (JF, JJ,
JK, JL, JN, and JQ) and the private sector in three subclasses(HD, HF, and HG). DDC and UDC cover the public and private sectors. DDC uses the 350 and 650 subclasses. UDC
uses the 00 (005 subclass), 35, and 65 subclasses.
Social groups (7.4) represents group-based social sciences. The category comprises four subcategories, based890

on four bases: gender (7.4.1), age (7.4.2), ethnicity (7.4.3),
and interest (7.4.4). The three classiﬁcation systems partiallycover the 7.4 category (see Tables 13 and 14).
To summarize, LCC, DDC, and UDC cover the humansociety diversiﬁed phenomena, but the coverage is incomplete and unsystematic.
Thought and Art
The products of the human intellect and the arts are represented in pillar 8, thought and art, which is divided into threemain categories: thought (8.1), literature (8.2), and the arts
(8.3). The three classiﬁcation systems cover the various ﬁelds.
Table 15 maps the knowledge covered by the main classes
of LCC, DDC, and UDC. Table 16 presents the speciﬁc
subclasses at the second level of each classiﬁcation.
Thought (8.1) is focused on the human thought andcomprises three subcategories: reason (8.1.1), representation(8.1.2), and relations (8.1.3). Reason (8.1.1) includes the ﬁeldof philosophy. LCC covers philosophy by the B, BC, BD, BH,
BJ, and BL subclasses. DDC covers philosophy by the 100,
110, 120, 140, 160, 170, 180, and 190 subclasses. UDC covers
philosophy by the 1, 101, 11, 13, 14, 16, and 17 subclasses.
Note that logic is traditionally part of philosophy, although it
is an independent ﬁeld (see category 8.1.3). Representation(8.1.2) is centred on the basics of languages and includes
philosophy of language and philology. LCC covers the category by the P subclass. DDC covers the category by the 401
subclass, and UDC covers it by the 80 and 81 subclasses.
The coverage is adequate. Relations (8.1.3) includes three
relation-based ﬁelds: logic, mathematics, and statistics. LCC
covers the category by the BC (logic), HA, and QA subclass,
DDC covers it by the 160, 310, and 510 subclass, and UDC
covers it by the 16, 31 and 51 subclasses. To summarize, LCC,
DDC, and UDC adequately cover the thought category.
Literature (8.2) includes one generic ﬁeld, literature, andis the study of written works of art and covers all forms,
genres, languages, eras, and places. Generally, literature isdivided into two generic parts: literary theory (8.2.1) andliterary forms (8.2.2). Literary theory (8.2.1) is covered by
LCC (PN), DDC (800), and UDC (82) subclasses. Literary
forms (8.2.2) is covered by LCC by the PA, PG, PJ, PK, PL,
PN, PQ, PR, PS, PT, and PZ subclasses. DDC covers thecategory by the 810, 820, 830, 840, 850, 860, 870, 880, and890 subclasses. UDC covers the category by the 82 subclass.
To summarize, LCC, DDC, and UDC adequately cover theliterature category.
The arts (8.3) represents ﬁelds that study the manifold
aspects of nonliterary art. It encompasses all forms of nonliterary art worldwide throughout human history. Generally,
the arts is divided into two generic parts, art theory (8.3.1)
and art works (8.3.2). Theory (8.3.1) is covered by the LCC
BH and NX subclasses. DDC is covered by the 700 subclass.
UDC covers art theory by the 7 subclass. Art works or art
forms (8.3.2) is covered by the LCC M, ML, MT, N, NA,
NB, NC, ND, NE, NK, TR and TT subclasses. DDC covers
the category by the 710, 720, 730, 740, 750, 760, 770, 780,

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TABLE 15.

Thought and art (Pillar 8) at the main classes.
Thought and art
10 Pillars

Categories
8.1. Thought
8.1.1. Reason
8.1.2. Representation
8.1.3. Relations

8.2. Literature
8.2.1. Theory
8.2.2. Forms

8.3. The arts
8.3.1. Theory
8.3.2. Forms

Fields

LCC

DDC

UDC

ClassesClassesClasses

Philosophy
Philosophy of language
Philology

B
P

100
400

8

Logic
Mathematics
Statistics

B; H; Q

100; 300; 500

1; 3; 5

Literary theory

P

800

8

Poetry
Prose
Drama
Essay

P

800

8

Philosophy of art
History of art

B; N

700

7

Conceptual art
Drawing
Painting
Sculpture
Photography
Printmaking
Tapestry
Dance
Music
Theater
Opera
Entertainment
Cinematography
Digital arts
Applied and design arts
Architecture

M; N; T700

7

and 790 subclasses. UDC covers the arts diversiﬁed works by
the 7, 72, 73, 74, 75, 76, 77, 78, and 79 subclasses. To summarize, LCC, DDC, and UDC adequately cover the literaturecategory.
To summarize, LCC, DDC, and UDC cover the thought
and art diversiﬁed phenomena. An overall analysis shows that
although some minor revisions are required, the coverage isadequate, complete and systematic.
Technology
The human technology is represented in pillar 9, technology, which deals with human-based technologies andtechnology-based professions. It is divided into three maincategories: theory (9.1), professions (9.2), and technologies(9.3). Note that pillar 9 is focused on human technology while
animal technology is studied by the biological sciences andrepresented in pillar 5 (nonhuman organisms). The three classiﬁcation systems cover the various ﬁelds. Table 17 maps theknowledge covered by the main classes of LCC, DDC, andUDC. Table 18 presents the speciﬁc subclasses at the second
level of each classiﬁcation.
Theory (9.1) is focused on the philosophical basis of thehuman technology. The category includes philosophy of technology, which explores the nature of technology and its social
effects. The category is covered in LCC by the technology (general; T) subclass, but the coverage is incomplete.
DDC covers the category in the philosophy and theory (601)subclass. UDC does not cover the philosophy of technology.
Professions (9.2) is focused on technology based professions, mainly on engineering. LCC covers engineering
diversiﬁed subﬁelds in 14 subclasses: TA, TC, TD, TE, TF,
TG, TH, TJ, TK, TL, TN, TP, UG, and VM. DDC covers engineering in 620 and 660 subclasses. UDC covers engineeringin 62, 63, 65, and 66 subclasses. The coverage, especially by
UDC and LCC, is extensive. Still, it is not systematic because
the user is required to delve down the classiﬁcation rank to
ﬁnd the topic he or she needs.
Technology (9.3) is focused on the diversiﬁed humanbased technologies. It includes the body of knowledge related

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TABLE 16.

Thought and art (Pillar 8) at the main subclasses.
Thought and art
10 Pillars

LCC

DDC

UDC

ClassesClassesClasses

Philosophy

B; BC; BD; BH;
BJ; BL

100; 110; 120; 140; 160;
170; 180; 190

1; 101; 11; 13;
14; 16; 17

8.1.2. Representation

Philosophy of language
Philology

P

400

80; 818.1.3. Relations

Logic
Mathematics
Statistics

BC; HA; QA

160; 310; 510

16; 31; 51

PN

800

82

Poetry
Prose
Drama
Essay

PA; PG; PJ; PK;
PL; PN; PQ; PR;
PS; PT; PZ

810; 820; 830; 840;
850; 860; 870; 880; 890

82

Philosophy of art
History of art

BH; NX

700

7

Conceptual art
Drawing
Painting
Sculpture
Photography
Printmaking
Tapestry
Dance
Music
Theater
Opera
Entertainment
Cinematography
Digital arts
Applied and design arts
Architecture

M; ML; MT; N;
NA; NB; NC;
ND; NE; NK;
TR; TT

710; 720; 730; 740; 750;
760; 770; 780; 790

7; 72; 73; 74; 75;
76; 77; 78; 79

Categories
8.1. Thought
8.1.1. Reason

Fields

8.2. Literature
8.2.1. Theory (literary theory)
8.2.2. Forms

8.3. The Arts
8.3.1. Theory
8.3.2. Forms

to all the discovered, invented, developed, and used technologies in all civilizations throughout human history. The
category encompasses manmade physical objects and processes, research methodologies, scientiﬁc applications, andproduction techniques. The category is divided into four mainsubcategories: sciences (9.3.1), needs and activities (9.3.2),
materials (9.3.3), and processes (9.3.4).
Sciences (9.3.1) includes technologies that are grounded
and centered on speciﬁc sciences. These technologies are
the technological counterparts of the related sciences:
nuclear technology; nanotechnology (technologies that sized
between 1 to 100 nanometers—NM, one billionth of a meter);aerospace technology (i.e., aviation and space); biotechnology; and computer technology. Note that computer technology is based on mathematics. Needs and activities (9.3.2)
explores technologies that are centered on speciﬁc humanneeds and activities. These technologies are the technological counterparts of the related ﬁelds: information technology, educational technology, food technology, military892

technology, sport technology, and transport-based technologies (e.g., automotive technology). Materials (9.3.3) explores
technologies that are centered on speciﬁc natural or manmade
materials that are used for achieving diversiﬁed purposes:
ceramic technology, glass technology, metal technology (e.g.,gold technology), mineral technology, and wood technology.
Processes (9.3.4) explores technologies that are centered on
speciﬁc processes that are used for achieving diversiﬁed purposes: cooling technology and heating technology, freezing
technology and melting technology.
The coverage of the 9.3 category by LCC, DDC, and UDC
is incomplete (see Tables 17 and 18). Upon reviewing thethree systems, one can see that very often they do not differentiate between the profession (i.e., engineering) and the products (i.e., technologies), between the technologies and therelated applied sciences, and between applied sciences andbasic sciences. The coverage of engineering, technologies,
basic sciences, and the related applied sciences is very often
intermingled; therefore, the coverage is clearly unsystematic.

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TABLE 17.

Technology (Pillar 9) at the main classes.
Technology
10 Pillars

LCC

DDC

UDC

FieldsClassesClassesClasses

Philosophy of technology
Engineering

T
T; U; V

600
600

6

Artiﬁcial intelligence
Biotechnology
Computer science
Materials science
Nanotechnology
Nuclear technology

T

000

0; 6

Educational technology
Food technology
Information technology
Ceramic technology
Glass technology
Iron technology
Mineral technology
Wood technology

T

600

6

LCC

DDC

UDC

FieldsClassesClassesClasses

Philosophy of technology
Engineering

T
TA; TC; TD; TE; TF; TG; TH;
TJ; TK; TL; TN; TP; UG; VM

601
620; 660

62; 63; 65; 66

Artiﬁcial intelligence
Biotechnology
Computer science
Materials science
Nanotechnology
Nuclear technology
Educational technology
Food technology
Information technology
Ceramic technology
Glass technology
Iron technology
Mineral technology
Wood technology
Cutting technology
Freezing technology

TP

000

00; 60; 64; 66

TH; TL; TR

680; 690

62; 68; 69

Categories
9.1. Theory
9.2. Professions
9.3. Technologies
9.3.1. Sciences

9.3.2. Needs and activities

9.3.3. Materials

9.3.4. Processes

TABLE 18.

Cutting technology
Freezing technology

Technology (Pillar 9) at the main subclasses.
Technology
10 Pillars

Categories
9.1. Theory
9.2. Professions
9.3. Technologies
9.3.1. Sciences

9.3.2. Needs and activities

9.3.3. Materials

9.3.4. Processes

To summarize, LCC, DDC, and UDC cover technology,
but the coverage is incomplete and unsystematic.
History
The recorded human history is represented in pillar 10, history, which includes theory, universal memory, and relations.

It is divided into three main categories: theory (10.1), universal memory (10.2), and relations (10.3). The three classiﬁcations cover the different perspectives of the human history.
Table 19 maps the knowledge covered by the main classes
of LCC, DDC, and UDC. Table 20 presents the speciﬁc
subclasses at the second level of each classiﬁcation.

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TABLE 19.

History (Pillar 10) at the main classes.
History
10 Pillars

LCC

DDC

UDC

ClassesClassesClassesCategories

Fields

10.1. Theory

Philosophy of history

C

900

9

10.2. Universal memory

History
Archeology

A; C; D; E-F; U

900

910.3. Relations

Genealogy

C

900

9

TABLE 20.

History (Pillar 10) at the main subclasses.
History
10 Pillars

LCC

DDC

UDC

ClassesClassesClassesCategories

Fields

10.1. Theory

Philosophy of history

C

901

93

10.2. Universal memory

History
Archeology

AZ; CB; CC; CD; CE ;CJ, CN; CR; CT; D; DA;
DAW; DB; DC; DD; DE;
DF; DG; DH; DJ; DJK;DK; DL; DP; DQ; DR;
DS; DT; DU; DX; E-F; U

930; 940; 950; 960;
970; 980; 990

902; 93/94

10.3. Relations

Genealogy

CS

920

92

Theory (10.1) is focused on the philosophical basis of thehuman history. The category contains the ﬁeld of philosophyof history. Note that the term “philosophy of history” refers to
the philosophical reﬂections on the human past and the humanexistences in time. The philosophical basis of history as an
academic discipline is dealt in the general memory (10.2)
category, as subﬁeld of history. LCC uses the C subclass.
DDC uses the 901 subclass, and UDC uses the 93 (930.1)
subclass.
Universal memory (10.2) includes two ﬁelds, history andarcheology. LCC covers the category in the following subclasses: AZ, CB, CC, CD, CE, CJ, CN, CR, CT, D, DA, DAW,
DB, DC, DD, DE, DF, DG, DH, DJ, DJK, DK, DL, DP, DQ,DR, DS, DT, DU, DX, E-F, and U. The coverage is comprehensive but not systematic, mainly because most subclasses
are dedicated to Europe and America, while Asia, Africa,and Oceania get one subclass each. DDC covers history andarcheology in the 930, 940, 950, 960, 970, 980, and 990 subclasses. UDC uses the 93/94, and 902 subclasses. Both DDC
and UDC seem to cover history and archeology adequately.
Relations (10.3) is focused on relations among people andincludes genealogy, the study of families and their history.
LCC covers genealogy in the CS subclass, DDC uses the 920
subclass, and UDC uses the 92 subclass.
To summarize, LCC, DDC, and UDC cover the humanhistory diversiﬁed phenomena.An overall analysis shows that
although some minor revisions are required, in particular,894

classes C and D of LCC, the coverage is adequate, complete,and systematic.

Discussion and Conclusions
An Overall Analysis
An overall analysis of the knowledge covered by LCC,
DDC, and UDC is presented in Table 21 and 22. Table 21
summarizes how the three systems cover the 55 subject categories of the 10-pillar model. The 55 categories are mutually
exclusive and collectively cover the broad spectrum of humanknowledge.
Of the 55 categories, 39 are represented by LCC, DDC,
and UDC, as follows: 1, 4, 5, 6, 7, 8, 9, 12, 13, 14, 16, 17, 18,
19, 20, 23, 24, 25, 27, 28, 30, 31, 32, 33, 34, 35, 40, 41, 42,
43, 44, 45, 46, 48, 49, 50, 53, 54, and 55. Two categories (2and 47) are represented by LCC and DDC. Three categories(15, 22, and 36) are represented by LCC and UDC. Two
categories (10 and 11) are represented by DDC and UDC.
Three categories (21, 26, and 39) are represented exclusively
by LCC. Six categories are not represented at all by the threesystems (3, 29, 37, 38, 51, and 52).
LCC covers the following 47 categories: 1, 2, 4, 5, 6, 7,
8, 9, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
26, 27, 28, 30, 31, 32, 33, 34, 35, 36, 39, 40, 41, 42, 43, 44,
45, 46, 47, 48, 49, 50, 53, 54, and 55. It does not cover the

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TABLE 21.

The knowledge covered by category.

10 pillars
Pillars / Categories
Pillar 1: Foundations
1.1. Theory
1.2. Context
1.3. Methodology
1.4. Mediation
Pillar 2: Supernatural
2.1. Theory
2.2. Mysticism
2.3. Religions
2.3.1. Ancient
2.3.2. Monotheism
2.3.3. Asian
2.3.4. Modern
2.3.5. Ethnic
Pillar 3 Matter and energy
3.1. Theory
3.2. Principles
3.3. Substances
Pillar 4 Space and earth
4.1. Theory
4.2. Space4.3. Earth
4.3.1. Surface and substance
4.3.2. Interrelations
Pillar 5: Nonhuman organism
5.1. Theory
5.2. Basic sciences
5.3. Health and well-being
Pillar 6: Body and mind
6.1. Theory
6.2. Basic Sciences
6.3. Health and well-being
6.3.1. Medical sciences
6.3.2. Paramedical studies
6.3.3. Complementary med.
Pillar 7: Society
7.1. Theory
7.2. Society-at-large
7.2.1. General
7.2.2. Area-based
7.3 Domains
7.3.1. Community
7.3.1.1. Communication
7.3.1.2. Contract
7.3.1.3. Codes
7.3.1.4. Conduct
7.3.2. Needs and activities
7.3.3. Management
7.4. Social groups
7.4.1. Gender
7.4.2. Age
7.4.3. Ethnicity
7.4.4. Interest
Pillar 8: Thought and art
8.1. Thought
8.1.1. Reason
8.1.2. Representation
8.1.3. Relations
8.2. Literature
8.2.1. Theory
8.2.2. Forms
8.3. The arts
8.3.1. Theory
8.3.2. Forms
Pillar 9: Technology
9.1. Theory
9.2. Professions
9.3. Technologies
9.3.1. Sciences
9.3.2. Needs and activities
9.3.3. Materials
9.3.4. Processes
Pillar 10: History
10.1. Theory
10.2. Universal memory
10.3. Relations

LCC

DDC

UDC

1
2
3
4

+
+

+
+

+

+

+

+

5
6

+
+

+
+

+
+

7
8
9
10
11

+
+
+

+
+
+
+
+

+
+
+
+
+

12
13
14

+
+
+

+
+
+

+
+
+

15
16

+
+

+

+
+

17
18

+
+

+
+

+
+

19
20
21

+
+
+

+
+

+
+

22
23

+
+

+

+
+

24
25
26

+
+
+

+
+

+
+

27

+

+

+

28
29

+

+

+

30
31
32
33
34
35

+
+
+
+
+
+

+
+
+
+
+
+

+
+
+
+
+
+

36
37
38
39

+

40
41
42

+
+
+

+
+
+

+
+
+

43
44

+
+

+
+

+
+

45
46

+
+

+
+

+
+

47
48

+
+

+
+

+

49
50
51
52

+
+

+
+

+
+

53
54
55

+
+
+

+
+
+

+
+
+

Unique categories+++ Indicates a covered category.

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TABLE 22.

The knowledge covered by pillar.
LCC

Pillar 1
Pillar 2
Pillar 3
Pillar 4
Pillar 5
Pillar 6
Pillar 7
Pillar 8
Pillar 9
Pillar 10
Overall

DDC

UDC

LCC, DDC, and UDC

Complete

SystematicComplete

SystematicComplete

SystematicComplete

Systematic

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+Indicates sufﬁcient coverage; blank indicates insufﬁcient coverage.

following eight categories: 3, 10, 11, 29, 37, 38, 51, and 52.
DDC covers the following 43 categories: 1, 2, 4, 5, 6, 7, 8, 9,
10, 11, 12, 13, 14, 16, 17, 18, 19, 20, 23, 24, 25, 27, 28, 30,
31, 32, 33, 34, 35, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
53, 54, and 55. It does not cover the following 14 categories:
2, 3, 15, 19, 21, 22, 26, 29, 36, 37, 38, 39, 51, and 52. UDC
covers the following 44 categories: 1, 4, 5, 6, 7, 8, 9, 10, 11,
12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 25, 27, 28, 30,
31, 32, 33, 34, 35, 36, 40, 41, 42, 43, 44, 45, 46, 48, 49, 50,
53, 54, and 55. It does not cover the following 11 categories:
2, 3, 21, 26, 29, 37, 38, 39, 47, 51, and 52.
Two conclusions emerge in the light of these ﬁndings.
First, none of the three systems is exhaustive, meaning LCC,
DDC, and UDC do not comprehensively cover human knowledge. Second, even collectively LCC, DDC, and UDC do notcover the broad spectrum of contemporary knowledge.
Table 22 summarizes how the three systems cover the 10
knowledge domains. Seven of 10 pillars are inadequately
covered. The knowledge coverage of pillars 1, 2, 4, 5, 6,
7, and 9 is incomplete and unsystematic. Three pillars areadequately covered. The knowledge coverage of pillars 3, 8,
and 10 is complete and systematic. In an overall analysis,none of the three systems adequately present contemporary human knowledge. Furthermore, even taken collectively,
LCC, DDC, and UDC fail to adequately present humanknowledge.
Methodological Consideration
Scholars who are familiar with the three systems haveraised two arguments about the methodology of the study and,
consequently, its ﬁndings and conclusions. The ﬁrst argument questions the focus on the top levels of the hierarchicalstructures. The library schemes may not address the topics
outlined in the 10 Pillars of Knowledge at the top levels ofeach scheme, but nearly all are covered by deeper levels of
the schemes.
In fact, at the beginning of the study, we delved into
the hierarchical structures and mapped the relevant topics
wherever they appeared in each library scheme. However,896

we decided to leave this practice and focus on the ﬁrst twolevels of the hierarchical structures. We realized that if wego all the way down the hierarchical structures, then each of
the systems covers all the topics. Because LCC, DDC, andUDC are aimed at classifying publications, they have to provide a practical solution for every publication. Practically, thismeans that the three systems cover all topics and all ﬁelds.
However, very often the practical solutions seem strange. For
example, as noted above, veterinary medicine is presented in
LCC by the SF (animal culture) subclass, which is a subclassof S (agriculture). Obviously, veterinary medicine is not a
subﬁeld of agriculture. Apparently, librarians and users needpractical guides to LCC, DDC, and UDC. But developing
such guides was not the goal of this study.
A hierarchical classiﬁcation should meet three conditions.
First, the categories are mutually exclusive, meaning they
do not overlap one another. Second, the categories are collectively exhaustive, meaning together they comprise all the
relevant categories. Third, the classiﬁcation can represent all
the relevant items without exception. This means that every
ﬁeld of knowledge is represented (i.e., can be placed) by atleast one category. LCC, DDC, and UDC may meet the third
condition and cover all ﬁelds of knowledge, but do they meetthe ﬁrst two conditions?
We decided to focus on the ﬁrst two levels of the hierarchical structures because these levels embody the essence of theclassiﬁcation system. Each level is viewed as an independentclassiﬁcation unit and needs to meet the three conditions.
The main classes of each classiﬁcation (i.e., the ﬁrst level)need to be mutually exclusive, meaning they do not overlap
one another, collectively exhaustive, meaning together they
comprise all the relevant classes, and represent all the relevant ﬁelds without exception. This means that every ﬁeld ofknowledge is represented by at least one of the main classes.
Each of the main classes establishes an independent classiﬁcation unit, which comprises main subclasses (i.e., thesecond level). The main subclasses need to be mutually
exclusive, collectively exhaustive, and represent all the relevant ﬁelds without exception. This means that every relevant
ﬁeld is represented by at least one of the main subclasses.

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In retrospect, this theoretical-based, methodological decision
to focus on the top levels of the hierarchical structures is justiﬁed by the ﬁndings of the study. The top levels, in manycases, are not systematic.
The second argument questions the focus on the terminology of the hierarchical tree (i.e., classes and subclasses)
while ignoring auxiliary tables and application guides. The
library systems include auxiliary tables and guiding tools that
may refer to all ﬁelds of knowledge. Ignoring them affects
the ﬁndings and conclusions of the study.
In fact, at the beginning of the study, we related to auxiliary tables and tools, but we decided to leave this practiceand focus on the terminology of the hierarchical structures.
A classiﬁcation system is a structured network of concepts.
The structure is essential as it represents the logical relations
among the linked concepts. The terminology is a fundamental element and comprises the structure’s building blocks. It
needs to be self-explanatory: “What you see is what you get.”
The auxiliary tools are not part of the structure, but rather
explain it. In retrospect, this theoretical-based, methodological decision to focus on the terminology of the systems isjustiﬁed by the ﬁndings of the study. The terminology, inseveral cases, is biased and misleading.
Conclusions
To determine if a system is unsystematic, we need an
exemplary case, and we found numerous examples. To determine if a system is biased, we need an exemplary case, and we
found several examples. To determine if a system is incomplete, we need to explore all the levels of the classiﬁcation.
Because we explored the top two levels only, the conclusions
regarding the knowledge covered by the three systems refers
only to the top two levels.
The inevitable conclusion needs to be explicitly spelled
out. The three great library classiﬁcation systems–LCC,
DDC, and UDC–fail to adequately and systematically present

contemporary human knowledge. They are unsystematic andbiased, and they are incomplete at the top two hierarchical levels. They suffer from critical problems that cannot be resolved
by revisions. The time has come to abandon these seminal
classiﬁcations and construct new constructions.
The study was primarily designed at evaluating thefunctionality of LCC, DDC, and UDC to adequately represent
contemporary human knowledge and to map the knowledge
they cover. Because we successfully placed all the relevant
classes and subclasses of LCC, DDC, and UDC in at least
one category of the 10-pillar model, as a by product, thestudy reevaluated and showed the adequacy of the 10 Pillarsof Knowledge map to represent human knowledge.
Acknowledgement
10 Pillars of Knowledge is © by Chaim Zins. LCC is ©
by LCC. DDC is © OCLC. UDC is © by UDC.
References
Burke, P. (2000). A social history of knowledge: From Gutenberg to Diderot(p. 268). Malden, MA: Blackwell.
Universal Decimal Classiﬁcation Summary. (2011). The Hague: UDC
Consortium, 2011. Available under Creative Commons licence at:
http://www.udcc.org/udcsummary/php/index.php
Zins, C. (2004). Knowledge mapping: An epistemological perspective.
Knowledge Organization, 31(1), 49–54.
Zins, C. (2006). Redeﬁning information science: From information science
to knowledge science. Journal of Documentation, 62(4), 447–461.
Zins, C. (2007). Conceptual approaches for deﬁning data, information, andknowledge. Journal of the American Society for Information Science andTechnology, 58(4), 479–493.
Zins, C. (2008). 10 pillars of knowledge: Map of human knowledge.
Retrieved from http://www.success.co.il/knowledge/Map/Map.html andhttp://www.success.co.il/knowledge /map/map.pdf
Zins, C. (2009). 10 pillars of knowledge: Map of human knowledge. In
G.M. Braga & L.V.R. Pinheiro, Desaﬁos do impresso ao digital: Questões
contemporâneas de informação e conhecimento [Challenges of the digitalprint: contemporary issues of information and knowledge]. (pp. 169–176).
Brasília, Brasil: IBICT.

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Appendix
Main Classes and Subclasses of LCC, DDC, and UDC Mapped in the Study
Library of Congress Classiﬁcation
Class A – General Works
Subclass AM Museums. Collectors and collecting
Subclass AS Academies and learned societies
Subclass AZ History of scholarship and learning. The humanities
Class B – Philosophy, Psychology, Religion
Subclass B Philosophy (General)
Subclass BC Logic
Subclass BD Speculative philosophy
Subclass BF Psychology
Subclass BH Aesthetics
Subclass BJ Ethics
Subclass BL Religions. Mythology. Rationalism
Subclass BM Judaism
Subclass BP Islam. Bahaism. Theosophy, etc.
Subclass BQ Buddhism
Subclass BR Christianity
Subclass BS The Bible
Subclass BT Doctrinal Theology
Subclass BV Practical Theology
Subclass BX Christian Denominations
Class C – Auxiliary Sciences of History (General)
Subclass CB History of Civilization
Subclass CC Archaeology
Subclass CD Diplomatics. Archives. Seals
Subclass CE Technical Chronology. Calendar
Subclass CJ Numismatics
Subclass CN Inscriptions. Epigraphy
Subclass CR Heraldry
Subclass CS Genealogy
Subclass CT Biography
Class D – World History (except American History)
Subclass D History (General)
Subclass DA Great Britain
Subclass DAW Central Europe
Subclass DB Austria – Liechtenstein – Hungary – Czechoslovakia
Subclass DC France – Andorra – Monaco
Subclass DD Germany
Subclass DE Greco-Roman World
Subclass DF Greece
Subclass DG Italy – Malta
Subclass DH Low Countries – Benelux Countries
Subclass DJ Netherlands (Holland)
Subclass DJK Eastern Europe (General)
Subclass DK Russia. Soviet Union. Former Soviet Republics – Poland
Subclass DL Northern Europe. Scandinavia
Subclass DP Spain – Portugal
Subclass DQ Switzerland
Subclass DR Balkan Peninsula
Subclass DS Asia
Subclass DT Africa
Subclass DU Oceania (South Seas)
Subclass DX Gypsies
Class E – History of the Americas[Subclass] 11–143 America[Subclass] 151–904 United States
Class F – History of the Americas[Subclass] 1–975 United States Local History[Subclass] 1001–1145.2 British America (including Canada),
Dutch America[Subclass] 1170 French America[Subclass] 1201–3799 Latin America, Spanish America

Class G – Geography, Anthropology, Recreation
Subclass G Geography (General). Atlases. Maps
Subclass GA Mathematical geography. Cartography
Subclass GB Physical geography
Subclass GC Oceanography
Subclass GE Environmental Sciences
Subclass GF Human ecology. Anthropogeography
Subclass GN Anthropology
Subclass GR Folklore
Subclass GT Manners and customs (General)
Subclass GV Recreation. LeisureClass H – Social Sciences
Subclass H Social sciences (General)
Subclass HA Statistics
Subclass HB Economic theory. Demography
Subclass HC Economic history and conditions
Subclass HD Industries. Land use. Labor
Subclass HE Transportation and communications
Subclass HF Commerce
Subclass HG Finance
Subclass HJ Public ﬁnance
Subclass HM Sociology (General)
Subclass HN Social history and conditions. Social problems.
Social reform
Subclass HQ The family. Marriage. Women
Subclass HS Societies: secret, benevolent, etc.
Subclass HT Communities. Classes. Races
Subclass HV Social pathology. Social and public welfare.
Criminology
Subclass HX Socialism. Communism. AnarchismClass J – Political Science
Subclass J General legislative and executive papers
Subclass JA Political science (General)
Subclass JC Political theory
Subclass JF Political institutions and public administration
Subclass JJ Political institutions and public administration(North America)
Subclass JK Political institutions and public administration(United States)
Subclass JL Political institutions and public administration(Canada, Latin America, etc.)
Subclass JN Political institutions and public administration(Europe)
Subclass JQ Political institutions and public administration(Asia, Africa, Australia, Paciﬁc Area, etc.)
Subclass JS Local government. Municipal government
Subclass JV Colonies and colonization. Emigration and immigration.
International migration
Subclass JX International law, see JZ and KZ (obsolete)
Subclass JZ International relations
Class K – Law
Subclass K Law in general. Comparative and uniform law.
Jurisprudence
Subclass KB Religious law in general. Comparative religious law.
Jurisprudence
Subclass KBM Jewish law
Subclass KBP Islamic law
Subclass KBR History of canon law
Subclass KBU Law of the Roman Catholic Church. The Holy See
Subclasses KD-KDK United Kingdom and Ireland
Subclass KDZ America. North America(Continued)

898

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Library of Congress Classiﬁcation (Continued)
Subclass KE Canada
Subclass KF United States
Subclass KG Latin America – Mexico and Central America –West Indies. Caribbean area
Subclass KH South America
Subclasses KJ-KKZ Europe
Subclasses KL-KWX Asia and Eurasia, Africa, Paciﬁc Area,
and Antarctica
Subclass KZ Law of nations
Class L – Education
Subclass L Education (General)
Subclass LA History of education
Subclass LB Theory and practice of education
Subclass LC Special aspects of education
Subclass LD Individual institutions - United States
Subclass LE Individual institutions - America (except United States)
Subclass LF Individual institutions - Europe
Subclass LG Individual institutions - Asia, Africa, Indian Ocean islands,
Australia, New Zealand, Paciﬁc islands
Subclass LH College and school magazines and papers
Subclass LJ Student fraternities and societies, United States
Subclass LT Textbooks
Class M – Music
Subclass M Music
Subclass ML Literature on music
Subclass MT Instruction and study
Class N – Fine arts
Subclass N Visual arts
Subclass NA Architecture
Subclass NB Sculpture
Subclass NC Drawing. Design. Illustration
Subclass ND Painting
Subclass NE Print media
Subclass NK Decorative arts
Subclass NX Arts in general
Class P – Language and Literature
Subclass P Philology. Linguistics
Subclass PA Greek language and literature. Latin language and literature
Subclass PB Modern languages. Celtic languages
Subclass PC Romanic languages
Subclass PD Germanic languages. Scandinavian languages
Subclass PE English language
Subclass PF West Germanic languages
Subclass PG Slavic languages. Baltic languages. Albanian language
Subclass PH Uralic languages. Basque language
Subclass PJ Oriental languages and literatures
Subclass PK Indo-Iranian languages and literatures
Subclass PL Languages and literatures of Eastern Asia, Africa, Oceania
Subclass PM Hyperborean, Indian, and artiﬁcial languages
Subclass PN Literature (General)
Subclass PQ French literature – Italian literature – Spanish literature –Portuguese literature
Subclass PR English literature
Subclass PS American literature
Subclass PT German literature – Dutch literature – Flemish literaturesince 1830 – Afrikaans literature – Scandinavian literature –Old Norse literature: Old Icelandic and Old Norwegian –Modern Icelandic literature – Faroese literature – Danish literature –Norwegian literature – Swedish literature
Subclass PZ Fiction and juvenile belles letters
Class Q – Science
Subclass Q Science (General)
Subclass QA Mathematics
Subclass QB Astronomy
Subclass QC Physics

Subclass QD Chemistry
Subclass QE Geology
Subclass QH Natural history – Biology
Subclass QK Botany
Subclass QL Zoology
Subclass QM Human anatomy
Subclass QP Physiology
Subclass QR Microbiology
Class R – Medicine
Subclass R Medicine (General)
Subclass RA Public aspects of medicine
Subclass RB Pathology
Subclass RC Internal medicine
Subclass RD Surgery
Subclass RE Ophthalmology
Subclass RF Otorhinolaryngology
Subclass RG Gynecology and obstetrics
Subclass RJ Pediatrics
Subclass RK Dentistry
Subclass RL Dermatology
Subclass RM Therapeutics. Pharmacology
Subclass RS Pharmacy and materia medica
Subclass RT Nursing
Subclass RV Botanic, Thomsonian, and eclectic medicine
Subclass RX Homeopathy
Subclass RZ Other systems of medicine
Class S – Agriculture
Subclass S Agriculture (General)
Subclass SB Plant culture
Subclass SD Forestry
Subclass SF Animal culture
Subclass SH Aquaculture. Fisheries. Angling
Subclass SK Hunting sports
Class T – Technology
Subclass T Technology (General)
Subclass TA Engineering (General). Civil engineering
Subclass TC Hydraulic engineering. Ocean engineering
Subclass TD Environmental technology. Sanitary engineering
Subclass TE Highway engineering. Roads and pavements
Subclass TF Railroad engineering and operation
Subclass TG Bridge engineering
Subclass TH Building construction
Subclass TJ Mechanical engineering and machinery
Subclass TK Electrical engineering. Electronics. Nuclear engineering
Subclass TL Motor vehicles. Aeronautics. Astronautics
Subclass TN Mining engineering. Metallurgy
Subclass TP Chemical technology
Subclass TR Photography
Subclass TS Manufactures
Subclass TT Handicrafts. Arts and crafts
Subclass TX Home economics
Class U – Military Science
Subclass U Military science (General)
Subclass UA Armies: Organization, distribution, military situation
Subclass UB Military administration
Subclass UC Maintenance and transportation
Subclass UD Infantry
Subclass UE Cavalry. Armor
Subclass UF Artillery
Subclass UG Military engineering. Air forces
Subclass UH Other services
Class V – Naval Science
Subclass V Naval science (General)
Subclass VA Navies: Organization, distribution, naval situation
Subclass VB Naval administration(Continued)

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Library of Congress Classiﬁcation (Continued)
Subclass VC Naval maintenance
Subclass VD Naval seamen
Subclass VE Marines
Subclass VF Naval ordnance
Subclass VG Minor services of navies
Subclass VK Navigation. Merchant marine
Subclass VM Naval architecture. Shipbuilding. Marine engineering
Class Z – Bibliography, Library Science
Subclass Z Books (General). Writing. Paleography. Book industries
and trade. Libraries. Bibliography
Subclass ZA Information resources (General)
Dewey Decimal Classiﬁcation
000 Computer science, knowledge & systems
020 Library & information sciences
060 Associations, Organizations, Museums
070 News media, journalism & publishing
100 Philosophy
110 Metaphysics
120 Epistemology
130 Parapsychology & occultism
140 Philosophical schools of thought
150 Psychology
160 Logic
170 Ethics
180 Ancient, medieval & eastern philosophy
190 Modern western philosophy
200 Religion
210 Philosophy & theory of religion
220 The Bible
230 Christianity & Christian theology
240 Christian practice & observance
250 Christian pastoral practice & religious orders
260 Christian organization, social work & worship
270 History of Christianity
280 Christian denominations
290 Other religions
300 Social sciences, sociology & anthropology
310 Statistics
320 Political science
330 Economics
340 Law
350 Public administration & military science360 Social problems & social services
370 Education
380 Commerce, communications & transportation
390 Customs, etiquette & folklore
400 Language
410 Linguistics
420 English & Old English languages
430 German & related languages
440 French & related languages
450 Italian, Romanian & related languages
460 Spanish & Portuguese languages
470 Latin & Italic languages
480 Classical & modern Greek languages
490 Other languages
500 Science
510 Mathematics
520 Astronomy
530 Physics
540 Chemistry
550 Earth sciences & geology
560 Fossils & prehistoric life
570 Life sciences; biology

580 Plants (Botany)
590 Animals (Zoology)
600 Technology
610 Medicine & health620 Engineering
630 Agriculture
640 Home & family management
650 Management & public relations
660 Chemical engineering
670 Manufacturing
680 Manufacture for speciﬁc uses
690 Building & construction
700 Arts
710 Landscaping & area planning
720 Architecture
730 Sculpture, ceramics & metalwork
740 Drawing & decorative arts
750 Painting
760 Graphic arts
770 Photography & computer art
780 Music
790 Sports, games & entertainment
800 Literature, rhetoric & criticism
810 American literature in English
820 English & Old English literatures
830 German & related literatures
840 French & related literatures
850 Italian, Romanian & related literatures
860 Spanish & Portuguese literatures
870 Latin & Italic literatures
880 Classical & modern Greek literatures
890 Other literatures
900 History
910 Geography & travel
920 Biography & genealogy
930 History of ancient world (to ca. 499)
940 History of Europe
950 History of Asia
960 History of Africa
970 History of North America
980 History of South America
990 History of other areas
Universal Decimal Classiﬁcation
0 Generalities
00 Prolegomena. Fundamentals of knowledge and culture.
Computer science.
01 Bibliography and bibliographies. Catalogues
02 Librarianship06 Museums
070 Journalism
08 Polygraphies
1 Philosophy. Psychology
101 Nature and role of philosophy
11 Metaphysics
13 Philosophy of mind
14 Philosophical systems
159.9 Psychology
16 Logic. Epistemology
17 Moral philosophy. Ethics
2 Religion. Theology
21 Prehistoric and primitive religions
22 Religions of the Far East
23 Religions of the Indian subcontinent
24 Buddhism(Continued)

900

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Universal Decimal Classiﬁcation (Continued)
25 Religions of antiquity. Minor cults and religions
26 Judaism
27 Christianity
28 Islam
29 Modern spiritual movements
3 Social Sciences
30 Theories and methods in social sciences
31 Demography. Statistics. Sociology
32 Politics
33 Economics
34 Law. Jurisprudence
35 Public administration
36 Social Welfare
37 Education
39 Ethnography. Customs. Manners. Traditions. Way of life. Folklore
5 Mathematics and Natural Sciences
50 Generalities about the pure sciences
51 Mathematics
52 Astronomy. Astrophysics. Space research. Geodesy
53 Physics
54 Chemistry. Crystallography. Mineralogy
55 Earth sciences. Geology, meteorology, etc.
56 Palaeontology
57 Biological sciences in general
58 Botany
59 Zoology
6 Applied Sciences. Medicine. Technology
60 Biotechnology
61 Medical sciences

62 Engineering. Technology in general
63 Agriculture and related sciences and techniques. Forestry. Farming.
Wildlife exploitation
64 Home economics. Domestic science. Housekeeping
65 Communication and transport industries. Business management.
Public relations
66 Chemical technology. Chemical and related industries
67 Various industries, trades and crafts
68 Industries, crafts and trades for ﬁnished or assembled articles
69 Building (construction) trade. Building materials. Building practiceand procedure
7 The Arts. Recreation. Entertainment. Sport
71 Physical planning. Regional, town and country planning
72 Architecture
73 Plastic arts
74 Drawing. Design, applied arts and crafts
75 Painting
76 Graphic art. Graphics
77 Photography and similar processes
78 Music
79 Recreation. Entertainment. Games. Sport
8 Language. Linguistics. Literature
80 General questions. Including: Philology. Rhetoric
81 Linguistics and languages
82 Literature
9 Geography. Biography. History
91 Geography. Exploration
929 Biographical and related studies
93/94 History. Science of history. Ancillary sciences. General history

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901