Search the library catalog to identify books, audiovisuals, or government documents on your topic.
These are common call number areas for history:
Call numbers A-K are shelved on the second floor; call numbers L-Z are shelved on the third floor.
These are common call number areas you are likely to find:
B -- philosophy, psychology and religion
E -- U.S. History
PN, PS -- literature, but especially subclass "PS" (American Literature)
N -- art and architecture
PA -- classical literature
R -- Medicine
Call numbers A - K are shelved on the second floor; call numbers L - Z are shelved on the third floor.
Remember to check the footnotes or endnotes as well as the bibliography in any scholarly book you use. This often leads you to a variety of possible additional sources, including primary sources.