Doing Research at the Library of Congress

IIB. The Four Ways to Find Proper Subject Headings

c. Follow subject tracings

The third way to find the right Library of Congress subject heading is to exploit a useful display feature within the catalog itself. Almost every catalog record for any book (or other format of material) contains what is called a "tracings field"; the tracings are the subject headings assigned to that work by the catalogers. An example is given in Figure 1, "Converting a Title into a Subject Category."

A researcher looking for works on the Cockney dialect might come across Peter Wright's Cockney Dialect and Slang through either a keyword or a title search. A glance at the bottom of the catalog record for this book, however, indicates that it has received the LCSH term English language--Dialects--England--London as its subject heading. The latter phrase groups together all of the works on that subject. This is especially important, because many of the relevant books do not use the word "Cockney" in their titles:

The third method, then, is to find any relevant works by any means you can think of--by author, by title, by keyword, by classification number--and then to display the retrieved records in the full format so that the tracings field shows up. (This field does not appear in the brief display, which is the default format. The tracings can be displayed by clicking on either the "Full" or the "Subjects/Content" file-folder tabs appearing above the default “Brief” display record.)

You can do something similar when you are using the old card catalog, which is more complete than the computer for pre-1968 records. As Figure 2 shows, a title card such as that for Leonard A. Stevens’ book Death Penalty will show you that the proper subject heading, in this case, is Capital punishment--United States. Remember to look at the bottom of any card in the card catalog--that’s where the tracings show up in the old format. The subject heading, as in this case, may point you to an entirely different alphabetical section of the catalog.

It is crucial to understand that neither keywords nor titles are the same as subject headings. The former are uncontrolled, variable, and unpredictable; finding them is a matter of unsystematic guesswork. Subject headings, in contrast, are standardized and can be found via predictable methods--methods that enable you to find them even if you have no prior subject expertise in the area you wish to research.

Some researchers, unfortunately, get in the habit of using only the tracings method to find appropriate subject headings. This is not advisable. If you look exclusively at tracings, you will miss possible cross-references to narrower or related terms, as well as alphabetically adjacent terms (particularly those that file ahead of your starting-point term--the computers cannot scroll upward from a starting point). Remember, too, that the tracings you find on catalog records are dependent on the keywords you use in your initial search. Thus, if you want books on blue crabs, but type in the more general keywords "Chesapeake Bay," you will get records that have valid tracings--but for the wrong level of specificity.