"A literature review is a body of text that aims to review the critical points of current knowledge on and/or methodological  approaches to a particular topic. They are secondary sources and discuss published information in a particular subject area, and sometimes information in a particular subject area within a certain time period.  Its ultimate goal is to bring the reader up to date with current literature on a topic and forms the basis for another goal, such as future research that may be needed in the area.

A literature review usually precedes a research proposal and may be just a simple summary of sources. Usually, however, it has an organizational pattern and combines both summary and synthesis. 

A summary is a recap of important information about the source, but a synthesis is a re-organization, or a reshuffling, of that information. It might give a new interpretation of old material or combine new with old interpretations. Or it might trace the intellectual progression of the field, including major debates. Depending on the situation, the literature review may evaluate the sources and advise the reader on the most pertinent or relevant of them.

Keep in mind that the main focus of an academic research paper is to develop a new argument, and a research paper will contain a literature review as one of its parts. In a research paper, you use the literature as a foundation and as support for a new insight that you contribute. The focus of a literature review, however, is to summarize and synthesize the arguments and ideas of others without adding new contributions."

The following resource include a number of interesting tips on conducting literature reviews:

This is a sample of books at Tufts and beyond that include helpful tips for conducting literature reviews and writing dissertations and theses.