Books are shelved in general subject categories using the Library of Congress classification system. You may want to supplement your use of the catalog book search with browsing shelf areas for your topic.
Books on the history of the Abolition movement are shelved on the library's upper level.
Browse for books in this area -
E441-453: Slavery in the United States. Antislavery movements
If you're looking to get started finding resources pertaining to the Abolition, you should start by searching the library's catalog. Some keywords you might consider using when searching for primary sources printed in published books include words such as Sources, Autobiography, Memoirs, and Speeches.