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University Library, University of Illinois at Urbana-Champaign

History 200B: Family, Gender, and Law

A course guide to library resources. Scope: 1800-present

Library Catalogs

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:

  1. The catalog should be an efficient instrument for ascertaining:
    • Whether the library owns a particular work specified by its title;
    • Whether the library owns a particular work specified by its author;
    • Which works by a particular author are in the library;
    • Which editions of a particular work are in the library.1
  2. The catalog should collocate records for works on a common subject under a single, standardized heading.

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:

Subject Headings in the Library Catalog

Subject headings in a library catalog have three functions:

  1. To collocate records for works on a common subject under a single, standardized heading.
  2. To help users evaluate the potential relevance of a work without having to examine the work itself.
  3. To enable a user, who has identified a catalog record for a relevant work, to find more works on the same subject.

The subject headings used in the Library 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.

Subject headings are created based on a principle known as "literary warrant". Literary warrant means that librarians establish subject headings when the published literature on the subject is sufficient to establish that subject as a field of inquiry. As you can see from this definition, one consequence of this principle is that subject headings are always slightly behind the curve of scholarly discourse, since scholars produce new knowledge, and librarians look to established fields of knowledge for the creation of subject headings.

The principle of literary warrant creates two important challenges for researchers. First, there are some subjects that are not new per se, but that have not been written about ever, or else not in sufficient quantity to justify the creation of a subject heading. One good example is Bonnie Mak's book How the Page Matters, the subject of which is the page (as in the page of a book). Clearly, the page is not a new concept, but there have been few (if any) books published on the subject, and it is therefore not a subject heading. Instead, the cataloger gave this book the following subject headings:

  • Books --Format --History.
  • Book design --History.
  • Graphic design (Typography) --History.

Believe it or not, there are at least two records in the Library Catalog for books on the history of the page!

The second challenge is that, for truly new subjects, there will be a lag between the subject's appearance in the published literature and the creation of a subject heading for that subject in the Library Catalog. For example, the World Wide Web is generally considered to have been "invented" when Tim Berners-Lee created the first graphical user interface for the Internet in 1990 (the Internet itself was actually created in 1965). Clearly there were many books written about the World Wide Web almost immediately after its creation, but the subject heading "World Wide Web" was not established until five years later, in 1995. If, therefore, you were researching the history of the World Wide Web, you should be aware that the subject heading "World Wide Web" would only taken you back to the date of the subject heading's creation (1995). Prior to that, catalogers were usually describing books on the World Wide Web with the subject heading "Internet", even though the Internet is a broader subject--the World Wide Web is a part of the Internet, but the Internet includes much else besides to the World Wide Web.

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.

You can browse subject headings in the Library Catalog from the "Browse Search" interface (select "Browse Search" from the search option at the top of the screen).

Some Example Subject Headings

  • Arranged marriage.
  • Asians --Foreign countries.
  • Child rearing --History.
  • Child welfare --History.
  • Children --Government policy.
  • Children --History.
  • Children's rights --United States --History.
  • Divorce --History.
  • Families --China --History.
  • Family --England --History.
  • Family --History.
  • Family --History --Periodicals.
  • Family policy --History.
  • Father and child.
  • Fatherhood.
  • Femininity --China.
  • Globalization --Social aspects.
  • Illegitimate children.
  • Intercountry marriage.
  • Marriage --History.
  • Marriage --India --History.
  • Marriage --Japan --History.
  • Marriage law --United States.
  • Marriage law --England --History.
  • Marriage law --Great Britain --History.
  • Masculinity --China.
  • Motherhood.
  • Parent and child.
  • Parenting.
  • Polygamy --United States --History.
  • Sex role --China.
  • Women peasants --China --History.

In order to browse a menu of subject headings in the Library Catalog, you must use the Catalog's "Browse Search":

Books as Primary Sources

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):

  • correspondence
  • sources
  • diaries
  • personal narratives
  • interviews
  • speeches
  • documents
  • archives
  • early works to 1800

Shelf Browsing

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 The Evening Crowd at Kirmser's: A Gay Life in the 1940s, has the call number 306.766 B814e, 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:

Digitized Book Collections (Ebooks)

In addition to the 14 million+ printed books available to you here in the Library, we also have a rapidly growing collection of digitized books. You can find ebooks in the Library Catalog, just as you would find print books. Ebooks also tend to be aggregated into collections:


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.