Short answer: the purpose of a literature review is to show what is already known about a topic, where the disagreements are, what methods have been used, and where new research can make a meaningful contribution.
A literature review is not a book report made of academic papers. It should not simply list “Author A said this, Author B said that.” A strong literature review organises the field. It shows patterns, gaps, tensions, assumptions, and unanswered questions.
What a literature review does
First, it gives context. Readers need to know why the research question matters and what earlier work has found. Second, it prevents duplication. Researchers should not present an old question as new because they failed to read the field. Third, it helps justify method. If previous studies were weak, narrow, outdated, or contradictory, the review can explain why a new approach is needed.
A literature review also helps identify concepts. Academic fields often use terms in specialised ways. A good review clarifies those terms and shows how different authors use them.
What makes one useful
A useful literature review is selective but fair. It includes the most relevant work, not every paper ever written. It does not hide inconvenient evidence. It distinguishes strong studies from weak ones. It explains why the reviewed material matters for the question being asked.
In short, a literature review is the bridge between existing knowledge and new research. Without it, a study floats in the air. With it, the reader can see exactly what problem the research is trying to solve.