A literature review, or lit review for short, is an overview of the information that has been published on a subject by researchers and scholars. Your purpose in a literature review is to give your readers a sense of the current state of research on a topic - what knowledge and ideas have been established? What are their strengths and weaknesses? How do various authors differ in their conclusions on this topic? What is unknown still?
A literature is not just a list of people or articles who have studied a topic, nor is it simply a summary of resources; a literature review should involve synthesis and analysis of the themes and trends on a topic.