Tertiary information is synopsized information. It has been edited and condensed to provide basic information in the form of entries in dictionaries, handbooks and encyclopedias. It is not timely, and is the least authoritative since it is far removed from the original primary information. To find any information, you need tools. In libraries there are two basic types of tools, catalogs and indexes.
Catalogs are lists of whole items in collections.
In libraries, catalogs list books, encyclopedias, journals, and videos, among others. Catalogs are usually organized by titles, authors and subjects. The CAT will help you find tertiary information in encyclopedias, handbooks and dictionaries, and secondary information in books and monographic series. Indexes point to information within whole items, such as chapters in books, articles within journals, and abstracts within conference proceedings. At Penn State there are many indexes, in print, on CD-ROM, and online.