Peter Matthiessen (May 22, 1927 – April 5, 2014) was an American novelist, naturalist, wilderness writer and CIA agent. A co-founder of the literary magazine The Paris Review, he was a three-time National Book Award winner. He was also a prominent environmental activist. His nonfiction featured nature and travel, notably The Snow Leopard (1978) and American Indian issues and history, such as a detailed and controversial study of the Leonard Peltier case, In the Spirit of Crazy Horse (1983).