[See also: How to write a research project. How to write the background, theory, method, analysis and discussion sections. How to write the introduction and conclusion. How to review the literature and how to structure a research paper. How to finish on time and how to reference properly. Part of the Craft of Research series. Full program here.]
The scholarly literature frames your research questions and informs your thinking. When you do a literature review you are developing your understanding of the conversation that is going on among experts on your topic.
Here are some posts on the subject: