Because of the way academic libraries are organized, fiction books are shelved together with literary criticism and studies about authors and their works. For example, copies of A Confederacy of Dunces by John Kennedy Toole will be shelved next to translations of the book, other books by Toole, and scholars' studies of the book and the author.
With that in mind, call numbers for American literature books begin with PS, while British and other English-language literature books start with PR. Within these call numbers, books are organized by time period, then by author's name. These call numbers are shelved on the 2nd floor of Howard-Tilton.
So for contemporary American literature, start browsing around call number PS 3550, which begins the section for books published 1961-2000. Books published since 2000 begin around call number PS 3600. For British literature, books published 1961-2000 begin with call number PR 6050, and books published since 2000 begin around call number PR 6100.
See the full description of the PR and PS sections at http://www.loc.gov/aba/cataloging/classification/lcco/lcco_p.pdf.
