Peer review is a process used to evaluate research proposals and publications before funding or publication. It involves subjecting research to critical evaluation by independent experts in the field. While peer review began in 18th century scholarly societies, it became institutionalized in the 20th century due to increased research and specialization. Peer review is applied to funding applications, research reports, conference presentations, journal articles, and published works. It aims to ensure only high quality research is funded and published, though it is not perfect and can introduce bias or conservatism.