A bibliography, also known as "references" or "works cited," is the list of sources used to derive information or data about the topic in the research paper. The sources can be journals, books, websites or periodicals. Bibliographic information contains following information:
• Author
• Title
• Publisher
However, information contained in Bibliography may differ depending on the writing style used.

Annotation is a synopsis and/or evaluation.

An annotated bibliography is the synopsis and/ or evaluation of the sources from which information or data regarding the topic has been drawn.

Depending on the type and depth of a research paper an annotated bibliography can give following information:

Summary: Depending on the project or assignment the annotated bibliography broadly summarizes the sources to answer the questions such as, what is the gist of the book? What are the topics covered in the book? What are the main arguments in the book that support your research topic?

Assessment: This includes the evaluation of the sources. For example was the book helpful in the research? Is the information in the book reliable? How does the reliability of source fare when compared to other sources used in the research paper? What is the main preposition of the source? Is the source biased or objective?

Reflection: Once the sources are summarized and evaluated, it is important to reflect on the role of the source in formulating your research. In this section the annotated bibliography answers questions such as, was the source helpful in writing the research paper? How have the arguments in the source helped you in forming an opinion about your own research project?

The format of annotated bibliography may vary depending on the writing style used. Generally the annotations for each source are written in a paragraph form. However, the lengths of the annotations vary depending on if only summaries of the sources are being discussed or a detailed evaluation of the sources is being done.

There are several reasons for using annotated bibliography, some of them are:

Helps you to prepare better for research project: When you have write an annotated bibliography, in order to summarize, evaluate and reflect you would tend to go through the sources more carefully which in turn will help you gain insight about your own research topic. Instead of merely gleaning through the sources to collect the information one begins to critically evaluate the sources. This will also help you know fallout of your own research paper which you can rectify

Helps other researchers: An extensive annotated bibliography is other researcher´s views on a particular topic. Your annotated bibliography on a particular topic may help other researchers to know about what is being said about the topic and other researcher´s annotated bibliography would help you too in the same way.