Entries in dictionaries, encyclopedias, and handbooks specific to the various disciplines can help to get you started on a topic. They can
See the (somewhat outdated) list of dictionaries and encyclopedias below.
Though it hasn't been thoroughly updated or re-worked in a while, this list will get you started. It is organized by discipline (Theology, Psychology, Sociology, Education), and offers call numbers. The call numbers should get you into the vicinity of additional at least print works of reference not listed here: