John Evelyn was an English writer, landowner, gardener, courtier and minor government official, who is now best known as a diarist. He was a founding Fellow of the Royal Society.

A diary is a written or audiovisual memorabilic record, with discrete entries arranged by date reporting on what has happened over the course of a day or other period. Diaries have traditionally been handwritten but are now also often digital. A personal diary may include a person's experiences, thoughts, and/or feelings, excluding comments on current events outside the writer's direct experience. Someone who keeps a diary is known as a diarist. Diaries undertaken for institutional purposes play a role in many aspects of human civilization, including government records, business ledgers, and military records. In British English, the word may also denote a preprinted journal format.