Jonathan Gathorne-Hardy (17 May 1933 – 16 July 2019) was a British author, known for biographies, including one of Alfred Kinsey, and books of social history on the British nanny and public school system. For his autobiography, Half an Arch, he received the J. R. Ackerley Prize for Autobiography in 2005. He also wrote novels and children's literature.
Born in Edinburgh, he was brought up in London, and educated at Port Regis School, Bryanston and Cambridge. As a boy, he was one of Benjamin Britten's favourites and he and his family provided the names for the characters in The Little Sweep. His involvement with Britten is described in John Bridcut's Britten's Children.
He subsequently worked in advertising and publishing.
His grandfather was Gathorne Gathorne-Hardy, 3rd Earl of Cranbrook. (The 1st earl and the 5th and current earl both share the same name.) His father was Surgeon-Commander Honorable Antony Gathorne Gathorne-Hardy, fourth child of the third Earl. His mother was Ruth Elizabeth Thorowgood. Edward Gathorne-Hardy and Robert Gathorne-Hardy were his uncles, and his aunt was Lady Anne Hill, wife of George Heywood Hill, who together founded the Heywood Hill bookshop in Mayfair.
- Chameleon (1967)
- The Office (1970)
- The Rise and Fall of the British Nanny (1972, reissued 1993) as The Unnatural History of the Nanny (USA)
- Jane's Adventures in and out of the Book (1966)
- Jane's Adventures on the Island of Peeg (1972)
- Jane's Adventures in a Balloon (1975)
- The Airship Ladyship Adventure (1975)
- The Public School Phenomenon, 597–1977 (1977), as Old School Tie – Phenomenon of English Public School (USA)
- Cyril Bonhamy v. Madam Big (1981)
- Love, Sex, Marriage and Divorce (1981)
- Cyril Bonhamy and the Great Drain Robbery (1983)
- Doctors: the Lives and Work of GPs (1984) (non-fiction)
- The Centre Of The Universe is 18 Baedekerstrasse (1985)
- Cyril Bonhamy and Operation Ping (1985)
- The City Beneath The Skin (1986)
- Cyril of the Apes (1987)
- The Munros' New House (1987)
- The Interior Castle: a life of Gerald Brenan (1994)
- The Twin Detectives (1995)
- Particle Theory: a novel (1996)
- A Bookseller's War: Heywood and Anne Hill (1997) (letters, editor)
- Alfred C. Kinsey. Sex the Measure of All Things: a biography (1998)
- Half An Arch (2004) (autobiography)
- Gathorne-Hardy, Jonathan (2004). Half an Arch: A Memoir. ISBN 9781857252019.
- "Jonathan Gathorne-Hardy". Laura Cecil (author's agent). Retrieved 20 March 2010.
- Jonathan Gathorne-Hardy, Half an Arch: a memoir (2004), pp. 55-56
- "Jonathan Gathorne Garthorne-Hardy". The Peerage.com. Retrieved 20 March 2010.
- Burke's Peerage, Baronetage and Knightage, 2003, vol. 1, p. 942
- "Lady Anne Hill". The Independent. 31 January 2007. Archived from the original on 14 June 2022.