Evan "Ev" Cooper (1926–1982/1983) from the United States was one of the first advocates of cryonics. In 1962, he privately published Immortality: Physically, Scientifically, Now, under the pseudonym Nathan Duhring, advocating what he called a "freezing program". In December 1963, he founded the Life Extension Society, the first cryonics organization in the world.
In 1962, shortly after Cooper's book was published, Robert Ettinger privately published his book The Prospect of Immortality that independently also suggested the idea of cryonics. While Ettinger's book received more publicity, the cryonics historian R. Michael Perry has written that "Evan Cooper deserves the principal credit for forming an organized cryonics movement".
Cooper ended his involvement in the cryonics and life extension movement in 1969. According to his former wife, Mildred, he "turned away from cryonics because of overload, burn-out, and a general sense that it was not going to be a viable option in his lifetime". For the last years of his life, Cooper was a sailor. He was lost in the Atlantic Ocean in December 1982 or the early 1983.