Klein began photographing science fiction conventions in the 1940s. His collection includes photographs, slides, and glass slides, as well as other memorabilia, including correspondence with Isaac Asimov, Frederik Pohl, L. Sprague de Camp, Robert A. Heinlein, and others, over a period of 40 years.
According to the news release from UC Riverside:
Klein agreed to donate his collection to UCR after developing a friendship with Melissa Conway, head of Special Collections and University Archives, “who greatly admired his encyclopedic knowledge,” according to the memorandum of understanding establishing the Jay K. Klein Endowed Fund for the Support and Preservation of Science Fiction and Fantasy Collections of the UCR Libraries.
The Eaton Collection is the largest publicly accessible collection of science fiction and fantasy in the world.