What is a Library Catalog?
When researching in a library, especially a research library, its catalog is probably the most important tool you will use, and one with which you should familiarize yourself as quickly as possible. Even if you think you have never used the Library Catalog here, you probably have and just do not realize it, since "Easy Search", the Library's federated search engine, sends all queries to the Library Catalog along with several other online research tools.
A library catalog is a database of records that identify and describe resources owned by the library. Most of these records describe published resources like books. Use the catalog to find both print sources and digitized sources in the Library's collections.
Many research libraries today will dress their catalogs up with fancy interfaces, making the catalogs appear to have far greater functionality than they actually do. You will be a much better user of library catalogs if you understand the purpose and functions of library catalogs, which are in fact very basic:
Digitization of library catalogs has made it possible to perform keyword searches on the records in the catalog. Aside from this innovation, and a few other conveniences, the library catalogs of today are essentially identical (in function) to library catalogs created a hundred years ago.
If you can't find your book in our Library Catalog, you should next check to see if it's available from an I-Share Library. To search all I-Share Libraries, switch to "Advanced Search" in our library's catalog, and select the "All I-Share Libraries" radio button.
After you have explored the books available to you here at the University of Illinois, and also at other I-Share libraries, you will want to expand your search using WorldCat:
If you find a book in WorldCat that you would like to use for your research, you can request it through Interlibrary Loan:
Why bother with subject headings in the online catalog when you can do keyword searching?
It’s true that you can find sources on a topic by doing keyword searches. But if you limit yourself to keyword searching, you are likely to miss important material on your topic that uses other terms. If you only need two or three books, you can probably find what you need by doing keyword searches, but if you are doing historical research, you can’t afford to miss critical material on your topic. For a comprehensive subject search, search with subject headings as well as keywords.
A good way to identify subject headings for a topic is to do a keyword search in the online catalog using terms you think describe the topic and try to identify a few relevant books. Look at the full record for those books to see what subject headings were used, then do another search on those headings.
As a rule of thumb, use fairly broad headings, as well as the specific ones that describe your topic, in order to make sure you haven't inadvertently eliminated relevant material that is contained within works of larger scope. Most likely you will find multiple headings to describe your topic, and you should use all of them. You can narrow your search in the online catalog by combining subject headings (as a phrase) with keywords, using the “Advanced Search” option.
Like most documents, books can be either primary or secondary sources, depending on the nature of your research questions.
Any books published in the time period you are studying can be used as primary sources in principle. To find them in library catalogs and digitized book collections, combine a subject search with a search limit by date of publication.
Primary source documents, whether they were published or unpublished at the time, are often collected and published as books at a later time. To find these kinds of books (as described above), use one or more of the following Library of Congress subject terms in your search (or keep an eye out for them while browsing subject headings):
After a new book is assigned subject headings, it is then “classified” according to the Dewey Decimal Classification. UIUC is the largest “Dewey” library in the world. In addition, we use a system called Superintendent of Documents Classification ("SuDocs") for U.S. government publications (based on issuing agency).
In Dewey, the first three numbers indicate the main subject, and additional numbers are added after a decimal point to narrow the subject. Books and journals on historical topics are usually classified in the 900s, although much of social history gets classified in the 300s, and the history of science, technology, and medicine is classified in the 500s and 600s. Religion is classified in the 200s, philosophy in the 100s, literature and literary studies in the 800s, and the fine arts in the 700s.
For more detail on the Dewey Decimal classification consult this Guide to the Dewey Decimal System.
In the 1960s, many libraries adopted the Library of Congress Classification (LCC), but by that time the University of Illinois Library already had more than four million volumes classified in Dewey. Some large academic libraries began using LC classification for new materials and left their older materials in Dewey, splitting their collection in two. University of Illinois debated this approach in 1979, but decided against it, primarily because of the potential inconvenience to our readers, who would have to go back and forth between the systems. Eventually we did adopt LC classification for Music, Law, and materials in Asian languages; older materials in those collections were retrospectively converted to LC classification. Many newer acquisitions, across all disciplines, are now being cataloged in LCC, resulting in a split collection.
In order to browse the shelves, you need to know this “classification number”. Once you have identified a few books on your topic by doing a subject search in the online catalog, you can browse the shelf under the same general number(s) to find related works. For example, if you know that the book Watergate: The Presidential Scandal that Shook America has the call number 973.924 Oℓ86w2016, you could go to the Main Stacks or the History, Philosophy, and Newspaper Library to browse the shelves under the same Dewey number to find related material.
Because so much of the Library collection is now stored in a high density, off-site storage facility, it's no longer possible to browse the collection as completely as it once was. You can, however, do "virtual shelf browsing" using the Library Catalog:
1. International Federation of Library Associations, Statement of Principles: Adopted at the International Conference on Cataloguing Principles, Paris, October 1961, ed. Eva Verona, Definitive ed. (London: International Federation of Library Associations Committee on Cataloguing, 1971), xiii.