The Olin Library includes numerous collections of comic books and books about comics. Specific call numbers for books are found in the online catalog, but when browsing the shelves, it helps to know something about them.
Books about comic books and strips can be found shelved in the library in the call number range PN 6700 through PN 6790. However, comic books about a specific topic might be classified with other materials on that topic; for example, Nelson Mandela : The Authorized Comic Book can be found with other materials about Mandela under the call number DT1974 .N47 2009. Works that address comic books as part of a broader topic might also be shelved elsewhere; Japanese Visual Culture : Explorations in the World of Manga and Anime can be found under NC1764.5 .J3 J37 2008 among books on the fine arts.
The broad topics indicated by the first letter of the "call number" are often broken down into subtopics with a second letter, and are then refined in much greater detail with the addition of numbers. A full listing of Library of Congress call numbers can be found here: http://www.loc.gov/catdir/cpso/lcco/
The digits in these call numbers are read as counting numbers, not as decimals as in the Dewey Decimal system. This means that DL 1175 is found between DL 1174 and DL 1179, well after DL 117 or DL 118.
This arrangement of books by subject matter makes shelf-browsing convenient. If you find a useful book, the books nearby on the shelf are likely to be closely related in topic.
Note that these call numbers are used both for the circulating collection and in the reference collection.