A literature review, generally, is a summary and synthesis of existing research on a topic. Most scholarly articles or papers include a literature review to introduce the research question or thesis. But some literature reviews stand alone as individual papers.
There are also different types of review articles that have other purposes; read more below.
If you are asked to write a literature review for an assignment, read the instructions and consult with your instructor to be sure you understand exactly what is expected of the literature review for this assignment.
Approaches for finding more sources related to key articles. Many library databases offer these features:
Google Scholar: look for Cited By and Related articles links
Esearch: look for References / Cited by links
Review articles are generally a kind of secondary source. That is, they are not presenting empirical findings from a single research project. They are, however, original, in the sense that the author is using skill, knowledge and creativity to compile and write something new about the material (books, articles) under review.
There are several kinds of review articles. Book Reviews are a special case, because sometimes they are written by experts but sometimes they are written by journalists or just fans of the book. Typically, a book review describes the main contents of the book, how it relates to existing ideas or works, and gives a judgment as to its value to various readers. Some book reviews are just a paragraph, but the reviews in scholarly journals can be several pages. In Esearch, you can limit search results to book reviews only, or screen book reviews out of the results, by clicking into the left-hand column under Content Type.
Stand-alone Review Articles or Literature Reviews are common in the social sciences. The authors of these articles are experts, usually scholars. The review articles will address a current topic, lay out the main theories or ideas, recent developments in research, and suggest where further research is needed.