The purpose of a literature review is to offer an overview of what is known about a topic. It will also evaluate the strength of the evidence on that topic. It usually contains a summary or an analysis of the key arguments in the existing literature. The literature may come from books, articles, reports, or other formats. Sources may contradict each other. A literature review also helps distinguish what research has been done and identify what needs further research. It does not present an original argument.
From the University of Toledo.
Thanks to these folks for background info and LibGuides templates.
Writing narrative literature reviews for peer-reviewed journals: secrets of the trade. Green B, Johnson C, Adams A. Journal Of Chiropractic Medicine. September 2006;5(3):101-117.