Use the Library of Congress Classification system to find the call number for your subject area. Then, browse the general and reference shelves in the library to discover books on your topic.
Serendipity can lead you to titles you never thought to search for and enhance your research in unexpected ways.
Subdivisions added to LCSH (Library of Congress Subject Headings) narrow broad topics and make it easier to zero in on relevant sources in a library catalog search.
For example, a search of the LCSH "New York (N.Y.)" in LC Authorities yields dozens of pages of subdivided headings related to NYC.
The chart below shows just a few of the common subdivisions you can add to a subject to narrow down results in a library catalog search.
E.g., "New York (N.Y.) -- Social life and customs"
Politics and government
Social life and customs
(Source: Oxford Guide to Library Research, 37-52.)