Start with a keyword search in the catalog. Once you have located a relevant item, you can look at the Library of Congress Subject Headings within the full record tab and follow those links to find related books.
Sample Subjects:
Peace-building, or Peace-building -- Africa [or other region or nation]
Allows you to search America History & Life and Historical Abstracts either together or separately. America History and Life, is an index for North American history consisting of journal articles, books, book chapters, dissertations & book reviews. Historical Abstracts, covers the history of the world from 1450 to the present (excluding the United States and Canada).