A literature review is a comprehensive study and interpretation of literature that addresses a specific topic.
Literature reviews are generally conducted in one of two ways:
1) As a preliminary review before a larger study in order to critically evaluate the current literature and justify why further study and research is required.
2) As a project in itself that provides a comprehensive survey of the works published in a particular discipline or area of research over a specified period of time.
Why conduct a literature review? They provide you with a handy guide to a particular topic. If you have limited time to conduct research, literature reviews can give you an overview or act as a stepping stone.
More: different types of literature reviews on how to conduct a literature review.