The literature review analyzes relationships and connections among different works. This differs from an annotated bibliography which provides a list and brief description of articles, books, theses, and other documents. The literature review should not merely list and summarize one piece of research after another.
Through analysis of major works and subsequent scholarship the lit review lays out the evolution of scholarship on a topic and establishes a context for further research. This will help you to establish why the topic is important and place your research in a theoretical context.
A literature review will help you to avoid redundancy in your own research and to identify new problems, possibilities for further research, and to expand upon or ask new questions. The literature review allows you as a researcher to enter into an ongoing conversation with other scholars and researchers.