A “review of the literature” is a classification and evaluation of what accredited scholars and researchers have written on a topic. Occasionally you will be asked to write one as a separate assignment, but often it is part of the introduction to an essay, research report, or thesis. In writing the literature review, your purpose is to convey to your reader what knowledge and ideas have been established on a topic, and what their strengths and weaknesses are. As a piece of writing, the literature review must be defined by a guiding concept (., your research objective, the problem or issue you are exploring, or your thesis). It is not just a descriptive list of the material available, or a set of summaries.
Be wary of too easily coming to the conclusion that nothing has been written on your topic. There are some topics so new that they have largely escaped previous academic enquiry. In practice, however, you will probably discover that almost any topic is connected to an existing body of research. If you are, say, studying alcohol abuse by young people in a small rural community in New South Wales, you need to look at the literature regarding the abuse of alcohol and other drugs in different parts of Australia, and in other countries.