Humphrey Richard "Hugh" Slater (1906–1958) was an English author and painter.
Born in Carlisle, Cumberland in 1906, he spent his early childhood in South Africa, where his father served in Military Intelligence in Pretoria, before returning to England. He attended the Slade School of Art in the mid-1920s, and exhibited an abstract painting at Lucy Wertheim's gallery, a leading London gallery. Painter William Coldstream considered him "a very gifted and rare artist".
Getting involved in anti-Nazi politics in Berlin in the early 1930s, he joined the Communist Party of Great Britain and in 1936 went to fight in the Spanish Civil War as Chief of Operations for the International Brigades.
Back in England, he helped Tom Wintringham set up the Osterley Park training centre in 1940 which taught guerilla warfare and street fighting for the Home Guard before being drafted into the regular army as a private. The public outcry led to questions being asked in Parliament and an article in the magazine Time. He was also editor of the short-lived magazine Polemic (1945–1947).
- 1941: Home Guard for Victory! Gollancz
- 1946: The Heretics
- 1948: The Conspirator
- 1955: Who rules Russia? Batchworth Press (London)
- 1958: The Channel Tunnel A. Wingate (London)
- 2009: Los herejes, Spanish translation of The Herectics; Galaxia Gutenberg/Círculo de Lectores (Barcelona). Translated by Montserrat Gurguí and Hernán Sabaté.
- 2009: El conspirador, Spanish translation of The Conspirator; Galaxia Gutenberg/Círculo de Lectores (Barcelona). Translated by M. Gurguí and H. Sabaté.
- "The National Archives".
- Buckman, David (13 November 1998). "Art-Historical Notes: Where are the Hirsts of the 1930s now?". The Independent.
- "War Office School (Lecturer)". 1 April 1941.
- "Wintringham Out". Time. 30 June 1941.
- Orwell, Sonia and Angus, Ian (eds.). The Collected Essays, Journalism and Letters of George Orwell Volume 2: My Country Right or Left. London: Penguin.
- "Fascimile". Archived 24 February 2007 at the Wayback Machine
- Orwell, Sonia and Angus, Ian (eds.). The Collected Essays, Journalism and Letters of George Orwell Volume 4: In Front of Your Nose (1945-1950). London: Penguin.