But despite all that, it can be helpful to go to the library, and browse the shelves. Every scholar has stories about finding great things by accident, just looking at the collections. You can start by finding one promising book, and just looking at the books around it. Or, you can find some promising call numbers, which can start your journey.
We use the Library of Congress system for arranging our books, which assigns a letter for a big general topic, and then numbers to get more specific. For instance:
D - World History (i.e., not North or South America)
E - United States history (Precolumbian societies, and national-level history)
F - Local United States History (states, etc.); other Western Hemisphere history, including Canada
Call Number examples:
E99 - Native American history
F631-645 - North Dakota History
All our D, E, and F books are on the third floor of Chester Fritz Library.