The Niels Bohr Library and Archives, American Institute of Physics, has released online the complete papers of Samuel A. Goudsmit (1902-1978) at Goudsmit co-discovered electron spin; helped lead the investigation of Nazi atomic bomb research in 1944-45; and was editor of the American Physical Society’s  Physical Review, the preeminent international physics journal, from 1950 to 1974.  He became a chief spokesman for American physics in the post-war period.  The  Goudsmit Papers (1921-1979, 39 linear feet, approximately 69,000 images) is a  major international collection of correspondence, research notebooks, lectures, reports, World War II science documents, and other material.  It contains especially strong sources on the development of quantum physics in Europe and its spread to the U.S. through the 1930s, German efforts to develop an atomic bomb during World War II, post-war physics research, and scientific publishing   Because of its breadth and depth it is the most used collection in AIP’s Library & Archives.  The project to digitize the Goudsmit Papers was funded in part by a grant from the National Historical Publications and Records Commission.