The link above will take you to the library's main page and SmartSearch
Try a search for Holocaust, Jewish (1939-1945)
Use the filters on the left to narrow and/or expand your search
Click on a title and then browse related materials by clicking on a subject
some examples: Jewish refugees -- Europe -- History -- 20th century OR Jews -- Europe -- Migrations -- History -- 20th century OR Humanitarianism -- History -- 20th century OR United Nations Relief and Rehabilitation Administration
History books are usually, but not always, in C, D, E and F. Find the subcategory you want to explore--for example, DQ--then look for call numbers starting with DQ in the library stacks (shelves).
Another strategy: once you've found a book on your topic in the library catalog (click for example) and on the shelf, look on the shelves nearby, or virtually browse the shelves by clicking on the call number in the catalog.