Read overviews to quickly grasp the basics of your topic, and to find clues to follow up on (such as citations to other sources). Don't cite overviews.

Find overviews in the Reference section on the first floor of Simpson Library. I recommend these reference books:

Some encyclopedias are online. Wikipedia is a good general-purpose encyclopedia, although its articles are not necessarily written by experts.

For topics regarding World War I, I recommend an online encyclopedia called the International Encyclopedia of the First World War.