The four most important tools for finding books are:
Books and journals are organized in the UIUC Library by subject. Upon receipt, new books are assigned subject headings and classification numbers. Print journals were cataloged in the same way.
Books are shelved according to their call numbers (see below). In addition to the main bookstacks, there are several departmental libraries which comprise the UIUC Library, and most of them maintain a core collection. The Main Library houses the History, Philosophy and Newspaper Library (HPNL), the Language and Literature Library, the International and Area Studies Library, the Rare Books and Manuscripts Library, the Social Sciences, Health, and Education Library, and several others. Departmental libraries located outside the Main Library that you may need to visit are the Communications Library, the Architecture and Art Library, and the Law Library. You'll find that there are fewer departmental libraries every year, but you can consult the most recent list of existing departmental libraries, along with their hours of operation, at library.illinois.edu, or see this list which includes virtual departmental libraries (biology, physics, business and other subjects that don't have their own library but do have a dedicated librarian and significant online resources).
Print books and journals in the Library are shelved either by Dewey Decimal Classification (DDC), or Library of Congress Classification (LCC). The bulk of the collection is classified in DDC, but newer acquisitions are increasingly classified in LCC. A lot of new graduate students are familiar with LCC from their previous colleges or universities. For help "crosswalking" from DDC to LCC, consult this guide: https://www.questionpoint.org/crs/html/help/en/ask/ask_map_lcctoddc.html .
The subject headings used in the card catalog and online catalog are standardized Library of Congress terms, which may be “subdivided” (made more specific) by geographic area, chronological period, genre, or sub-topic. The language of subject headings is not at all intuitive or natural, so you shouldn’t hesitate to ask a librarian for help in finding the correct subject headings.
A good way to identify subject headings for a topic is to do a keyword search in the Library Catalog using terms you think describe the topic in order 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.
See list of examples on the left.
You will observe that there is considerable redundancy in subject headings, reflecting different cataloging practices at different times. You may need to use several variants to identify all the books you need.
|Women travelers||Travel writing||Travelers' writings, English|
|Travel in literature|
|English diaries||Diaries-Women authors|
|Women authors, English-Diaries||Women-England-Diaries|
Why bother with subject headings in the online catalog when you can do keyword searching?
It’s true that developing facility with subject headings was more critical in the era of card catalogs. They provided the only subject access to library materials. In online catalogs, you can often identify material on a topic quite easily by searching on keywords. But if you limit yourself to keyword searching, you are likely to miss important material on your topic that uses other terms. For an undergraduate term paper, a keyword search may turn up a few good sources, and that may be sufficient for the purposes of the assignment. But when you’re doing historical research, you won’t want to miss critical material on your topic. A systematic, comprehensive subject search requires searching with subject headings as well as with keywords.
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 (zzzzz), consult the Dewery summary tables.
In the 1960s, many libraries adopted the Library of Congress Classification, but by that time the UIUC 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. Here at UIUC we 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 being cataloged in LC.
In summary, use the Library Catalog when you have a reference or citation to a particular book or journal you want to find in the Library, or when you want to do a subject search to find books on a particular topic.