A literature review serves several purposes. For example, it

• provides thorough knowledge of previous studies; introduces seminal works.
• helps focus one’s own research topic.
• identifies a conceptual framework for one’s own research questions or problems; indicates potential directions for future research.
• suggests previously unused or underused methodologies, designs, quantitative and qualitative strategies.
• identifies gaps in previous studies; identifies flawed methodologies and/or theoretical approaches; avoids replication of mistakes.
• helps the researcher avoid repetition of earlier research.
• suggests unexplored populations.
• determines whether past studies agree or disagree; identifies controversy in the literature.
• tests assumptions; may help counter preconceived ideas and remove unconscious bias.

A "Lit Review" is a comprehensive and up-to-date overview of the principal research about the topic being studied.

The review helps form the intellectual framework for the study.

The review need not be exhaustive; the objective is not to list as many relevant books, articles, reports as possible.

However, the review should contain the most pertinent studies and point to important past and current research and practices in the field.