To gather background information on your topic and to learn about research and scholarship in the field are good reasons to start with reference material.
For Social Science research, a good starting point is the International Encyclopedia of the Social & Behavioral Sciences which besides sociology includes:
You can also try Credo Reference, an online database with approximately 400 reference books, including:
as well as a range of subject-specific reference books including Sociology.
Oxford Bibliographies provides a seamless pathway to the most accurate and reliable resources for a variety of academic topics. Written and reviewed by academic experts, every article in the Oxford Bibliographies database is an authoritative guide to the current scholarship, containing original commentary and annotations. The link below goes directly to the Sociology Bibliographies.
Subject dictionaries, encyclopedias, and handbooks typically provide background essays, definitions, broad overviews of various topics, or other pertinent facts.