Depending on your research question, you will want to consult books, scholarly articles, and other media (such as conference proceedings, artifacts, film, etc).
Do you need background information?
Are you aware of authors for your topic?
Should you limit your results to time periods?
Should you limit your results to geographical locations?
Do you want to limit your sources?
What databases should you use?
First think about your topic. Questions to consider:
A question is asked
A topic is investigated
Information is discovered
Information is published
Published information is indexed
Information is searched, found, and read
transmission of information raises new questions
fueling new investigations