This first link on the left is to a 4 volume paper encyclopedia in the Reference Room. It is an excellent place to brainstorm a topic, get background information, and find a bibliography you can mine for pertinent book and journal articles.
The Wikipedia article is also a good place to get ideas about narrowing the topic.
The other links go to CQ Researcher. This resource provides background information, statistics, and pro/con arguments for topics. Each article also has a bibliography to lead you to other resources.