Librarians in particular appreciate books that have a good index and may be more likely to purchase such books than those with only a minimal or sketchy index. Likewise, course instructors may be more likely to adopt a book that has an excellent, useful index. For More Information or more information than is presented here on style and procedures for indexing, refer to chapter 17 of The Chicago Manual of Style , 14th ed., published by the University of Chicago Press, 1993. Such an indexer also clearly pictures the potential readers and anticipates their special needs. The author is often the best person to index a book because he or she knows the scope and limitations of the work and also knows the work's intended audience.
Many authors ask if it's possible for a computer to generate the index.
The fact is that indexing is too complex a task to be done well by a computer. The most obvious reason for this is that the best term to identify a topic might not appear in exactly that form on the page where the topic is discussed, or might appear ambiguously. A good index will take into account the needs of the work's intended readers and requires thoughtfully worded main entries, subentries, and cross-references. A computer can, at best, generate only a concordance, that is, a list of words or phrases that can be found in the text. The computer cannot reword entries so that they conform to standard indexing style, nor can it distinguish between incidental material and topics that are central to the text.