An annotated bibliography is a list of works (books, articles, other publications) on a particular subject.
Each annotation in the bibliography can be written as a description or evaluation of the work or include both. The length of an annotation is typically one paragraph that is well written, conscise and containing the following elements. If the annotation includes both descripton and evaluation, the length could be two paragraphs.
All of the citations in an annotated bibliography should follow the format of the style you have choosen such as MLA,APA, Chicago, Turabian, etc.
If you are writing your annotated bibliography for a class you should always follow your instructors directions.
A typical annotation can contain all or part of this outline: