John K. Mahon (1912-2003) grew up in Iowa, the son of a grocer (1934-1942) and an avid member of the Boy Scouts of America; his rural upbringing gave him a life long love of the outdoors. During World War II, he served as an officer in the Ninth Armored Division of the Fifth Army in Europe (1942-1946). He attended Swarthmore College as an undergraduate and received his Ph.D. from UCLA. He joined the faculty of the history department at the University of Florida in 1954, was chairperson of the department from 1965 to 1973, and retired in 1982 after 28 years as a professor. His academic career focused on military history, a subject he became interested in during his own time of service. Mahon's most famous publication was his History of the Second Seminole War, largely regarded as the authoritative source on the subject. He was also the author of a well-received history of the War of 1812 and other works of military history. In Gainesville, Mahon was became well known for his environmental activism. He served as an officer in various environmentalist groups for many years, and became especially prominent after his official retirement from UF.