Once you have selected a topic, it's a good idea to locate background information. You can get a feel for the subject with an overview of the topic and its sub-areas. General sources also provide important references for beginning your research. Here are some tools that can help in this process:
Begin with your own textbook. Check sources that are cited.
Handbooks, Subject Encyclopedias and Subject Directories
Handbooks provide information from authorities in the subject area. Experts in the field write the chapters. Generally there are a large number of authors for a work. Handbooks are more comprehensive than textbooks. Generally chapters contain extensive reference lists.
Some subject areas publish annual reviews covering selective and evaluative reviews of important happenings for the year. Check at the library service desk for help in locating appropriate sources.