Brian Sutton Smith (July 15, 1924 – March 7, 2015), better known as Brian Sutton-Smith, was a play theorist who spent his lifetime attempting to discover the cultural significance of play in human life, arguing that any useful definition of play must apply to both adults and children. He demonstrated that children are not innocent in their play and that adults are indeed guilty in theirs. In both cases play pretends to assist them in surmounting their Darwinian struggles for survival. His book "Play As Emotional Survival" is a response to his own deconstruction of play theories in his work, "The Ambiguity of Play" (1997, Harvard University Press).