Annotated bibliographies explore the research already conducted on a particular subject. As with any bibliography, an annotated bibliography is an alphabetical list of research sources surrounding a particular topic, and is either summative or evaluative. Along with the standard bibliographic data of title, author, date and publisher, a summative annotated bibliography contains a concise, but thorough summary of what the source covers and its main arguments. An evaluative annotated bibliography has this information along with an analysis of the source's relevance and credibility. Producing an annotated bibliography is often one of the first steps in a research project or may be a project in its own right.
At the start of a project, it's often difficult to identify which sources are relevant to your study. Analyzing the main argument of each source and its relevance to the subject gives you a list to refer back to in subsequent stages of your project. It also helps you decide where your topic of study fits in a broader context. The annotated bibliography is also of use to your teachers who can identify that you've read the main literature on your subject and point out any sources that you've missed. It's also of use to readers of the bibliography, especially other students, as it provides background material to your work. They can also use it to find relevant sources for their own work.
Creating an annotated bibliography hones your research skills, as its quality relates to the usefulness of the sources you've identified. The key to a successful annotated bibliography is a well-defined topic statement on the subject that you're investigating. The subject of the bibliography should be broad enough that you find enough sources, yet not too broad that you miss any key literature. Finding sources that offer contradictory views on the subject is part of the process, as is judging the credibility of the sources and their content. Following the trail of citations from one source to another is one way to identify relevant and useful sources.
Analysis skills come into play when summarizing the main argument of each source. In your annotation, give the main argument, some of the points used to back up the argument and the conclusions made. For an evaluative annotated bibliography, also evaluate the methods of investigation in the report and decide on its credibility. Finishing with the relevance of this source to your investigation allows you to link this analysis to your own needs. Writing skills are needed in detailing all of this information in about 150 to 200 words.