Books are shelved in general subject categories using the Library of Congress classification system. You may want to supplement your use of the catalog with browsing shelf areas for your topic.
BF -- Psychology
HM -- Sociology
HQ -- Family, Marriage, Women
QH -- Biology
QP -- Physiology
Google Books
Google is in the midst of an ambitious project to digitize books from publishers and in libraries. Those that were published before 1924 are in full text; those still potentially under copyright can be searched, but not viewed in full. It offers an interesting way to locate very specific words, phrases, and citations, particularly in older books. Using the advanced search you can limit a search to books that are full text or published within a range of years.
