Peer review is the assessment by experts of material submitted for publication. The peer reviewer serves the editor by substantiating the quality of the manuscript, and serves the author by giving constructive criticism. This system has benefits and drawbacks, including the tendency to select against novel work. Reviewers, whose work is generally unpaid, tend to be academicians who review for several journals and are authors and editors themselves. Editors often blind reviewers to authors to reduce bias, but reviewers frequently recognize the author anyhow. Blinding authors to reviewers may protect the reviewer. Manuscripts rejected by one journal because of peer review are usually published in another. Since peer review serves to validate the quality of the biomedical literature, the process should be valid itself.