A literature review is a means of demonstrating an author's knoweldge about a particular field of study, including vocabulary, theories, key variables and phenomena, and its methods and history. Conducting a literature review also informs the student of the influential researchers and research groups in the field.
Randolph, Justus J. "A Guide to Writing the Dissertation Literature Review."Practical Assessment, Research & Evaluation 14.13 (2009): 1-13.
Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination. London: Sage Publications, 1998, p.27.