A literature review is a piece of writing intended to critically evaluate material that has been published on a certain topic or research problem.
Literature reviews can...
Define and clarify a problem
Summarize previous investigations to inform the reader of the state of research
Identify relations, contradictions, gaps, and inconsistencies in the literature
Suggest the next step or steps in solving the problem
A literature review can be published as a free-standing piece of writing or as a section of a larger work. For example, literature reviews are often published as a book chapter or within the introduction of a scholarly research article. Literature reviews should follow the general guidelines of an appropriate style and formatting guide, such as APA, MLA, or Chicago.