What is an annotated bibliography?
An annotated bibliography is a list of citations followed by a descriptive summary and sometimes an evaluation. Sometimes the annotation will reflect the applicability of the source to the needs of the researcher.
The purpose of an annotated bibliography is to inform the reader of the relevance, accuracy, and quality of the sources cited. The length can vary, in terms of number of annotations and length of the annotations - please check with your instructor for his or her directions.
Gurko, Leo. Ernest Hemingway and the Pursuit of Heroism. New York: Crowell, 1968. This book is part of a series called "Twentieth Century American Writers": a Brief Introduction to the Man and his Work. After fifty pages of straight biography, Gurko discussed Hemingway's writing, novel by novel. There's an index and a short bibliography, but no notes. The biographical part is clear and easy to read, but it sounds too much like a summary.
Example borrowed from the Writing Center at UNC-Chapel Hill.