A literature review is a systematic and comprehensive analysis of books, scholarly articles, grey literature, and other sources relevant to a specific topic providing a base of knowledge on a topic. Literature reviews are designed to identify and critique the existing literature on a topic to justify your research by exposing gaps in current research.  This investigation should provide a description, summary, and critical evaluation of works related to the research problem and should also add to the overall knowledge of the topic as well as demonstrating how your research will fit within a larger field of study.  A literature review should offer a critical analysis of the current research on a topic and that analysis should direct your research objective. This should not be confused with a book review or an annotated bibliography both research tools but very different in purpose and scope.  A literature review can be a stand-alone element or part of a larger end product, know your assignment.  The key to a good literature review is to document your process.