For a regular contribution to a peer-reviewed scientific journal, a paper must meet four criteria before it is publishable:

An exception is made for the third requirement, novelty, for an important category of papers: the review article. Review articles, as the name implies, provide a critical evaluation of previously published work on a specific topic. Reviews tend to be quite popular with readers because they pack a lot of information in a small space, giving readers a great return on their invested time. They are a gift. Most readers do not have the time or inclination to thoroughly research the full literature on a specific topic and so greatly appreciate it when an author reports on the results of their thorough review of the topic. “Mini-reviews” are becoming increasingly popular as well (more on that in Section 11.3).