This collection consists of reports, letters, books, slides, and other materials documenting Hymer Friedell's work on the biological effects of radiation between 1943 and 1996. Much of the material dates from the Manhattan Project era and shortly thereafter. Of particular interest are slides documenting the aftermath of the Hiroshima bomb (1945) and a trip to Moscow (1966), books about the Manhattan project, and retrospective accounts of Friedell's work from the 1990s.