The Collection contains correspondence, notebooks, manuscripts of both published and unpublished articles and lectures, personal and professional memorabilia, photographs, movie films, and tape recordings. They document the personal life and career of a creative mathematician and key figure in the technical development of America's nuclear weaponry. The collection documents nearly the entirety of Ulam's life, but the core of the collection reflects the years after his arrival in the United States in 1935, and particularly after he began as a researcher at Los Alamos Scientific Laboratories in 1945. From 1935 on, Ulam was heavily engaged in publication, teaching, consulting, and traveling as a visiting lecturer at universities and scientific symposia, and most importantly, he was involved in the development of the atomic and hydrogen bombs. The Ulam Papers constitute a rich resources for study of the early years of nuclear weapon development in the United States, and though it is relatively lacking in technical scientific detail, the webs of relationships. Ulam's professional correspondence with fellow scientists as well as his original research materials are also noteworthy aspects of the papers.