Ken Slater (1917–2008) was a British science fiction fan and bookseller. In 1947, while serving in the British Army of the Rhine, he started Operation Fantast, a network of science fiction fans which had 800 members around the world by 1950 though it folded a few years later. Through Operation Fantast, he was the major importer of American science fiction books and magazines into Britain - an activity which he continued, after its collapse, through his company Fantast (Medway) up to the time of his death. He was a founder member of the British Science Fiction Association in 1958.