Books relevant to women's and gender studies are all over the library. The main area will be books starting with the call number "HQ." You can also look by subject heading or keyword. Some search terms to try:
Keep in mind that the "official" subject headings can be slow to catch up to theory and current political/social realities, so books on queer theory might be grouped under a subject heading like "homosexuality--philosophy." For that reason keyword searches can be a better starting point.