An annotated bibliography is a list of sources that includes a citation and a description for every source. Sometimes the description is a simple summary, other times, the description includes a summary and some form of evaluation. The evaluation can be opinions on the quality of the source or on how the source might help your project.
Aulich, James. War Posters: Weapons of Mass Communication. New York: Thames & Hudson, 2007.
A book that accompanied an exhibition of war and propaganda posters at the Imperial War Museum in London, with commentary on the posters themselves and the context of their creation and use.
The chapter on the Second World War, particularly the portions on the posters and propaganda created in Great Britain, will be helpful to me. I may use some of the images of the posters themselves and of the posters displayed to help create the setting for my character.
Note the three parts of this example: the citation (in Chicago Style) at the top, a brief sentence summary of the book in the middle (this part may need to be longer or more detailed than the example here), and two sentences describing the parts of the book that will help me and how I plan to use them.