John Freely was born in 1926 in Brooklyn, New York to Irish immigrant parents, and spent half of his early childhood in Ireland. He dropped out of high school when he was 17 to join the U. S. Navy, serving for two years, including combat duty with a commando unit in the Pacific, India, Burma and China during the last year of World War II. After the war, he went to college on the G. I. Bill and eventually received a Ph.D. in physics from New York University, followed by a year of post-doctoral study at Oxford in the history of science. He worked as a research physicist for nine years, including five years at Princeton University. In 1960 he went to İstanbul to teach physics at the Robert College, now the Boğaziçi University, and taught there until 1976. He then went on to teach and write in Athens (1976-79), Boston (1979-87), London (1987-88), İstanbul (1988-91) and Venice (1991-93). In 1993 he returned to Boğaziçi University, where he teaches a course on the history of science. His first book, co-authored by the late Hilary Sumner-Boyd, was Strolling Through İstanbul (1972). Since then he has published more than forty books.