In 1962 he privately published Immortality: Physically, Scientifically, Now under the pseudonym 'Nathan Duhring', a book that advocated Cryonics under the name of a "freezing program". While Ettinger's book received more publicity and had greater scientific rigor, long-time cryonics historian Michael Perry has written "Evan Cooper deserves the principal credit for forming an organized cryonics movement."
Believing it would not be a plausible option in his lifetime, Evan Cooper ended his involvement in cryonics in 1970. He was a boat carpenter and sailor for the next 13 years of his life until being lost at sea.
Unlike Robert Ettinger he had no scientific training, and so his proposals of using arctic and Antartic storage lacked scientific rigor.