George Powers Cockcroft, widely known by the pen name Luke Rhinehart, was an American novelist, screenwriter, and nonfiction writer. He is best known for his 1971 novel The Dice Man, the story of a psychiatrist who experiments with making life decisions based on the roll of a dice.

The Dice Man was critically well received and a commercial success. It quickly became and remains a cult classic. It was followed by two spiritual sequels, Adventures of Wim (1986) and The Search for the Dice Man (1993), as well as a companion volume called The Book of the Die (2000). Rhinehart wrote several other novels between 1986 and 2016 though none achieved the success of The Dice Man.

He was born in the United States, son of an engineer and a civil servant. He received a BA from Cornell University and an MA from Columbia University. Subsequently he received a PhD in psychology, also from Columbia. He married his wife, Ann, on June 30, 1956. He has three children. After obtaining his PhD, he went into teaching. During his years as a university teacher he taught, among other things, courses in Zen and Western literature. He first floated the idea of living according to the casting of dice in a lecture. The reaction was reportedly of equal parts intrigue and disgust, and it was at this point he realized it could become a novel.