Ken Kesey was an American novelist, essayist, and countercultural figure. He is best known for his novel One Flew Over the Cuckoo's Nest, which was adapted into a Broadway play and film. He also wrote Sometimes a Great Notion and other works. Kesey was a key figure in the 1960s psychedelic movement, and was associated with the Merry Pranksters. He was also an early proponent of the use of LSD and other psychedelic drugs.