Scope and Contents: Correspondence with Hans von Euler about their experiments on induced cancer; correspondence with Charles Huggins (restricted); papers on the discovery and application of hafnium (e.g. Auer Gesellschaft, Philips, Metropolitan-Vickers); newspaper clippings, honours and prizes; old bills; proofs for "Radioactive Indicators" and "Lehrbuch der Radioaktivität"; box of Hevesy's notebooks - from earlier times as well as from Hilde Levi's experiments in the 1930s; various scientific notes, e.g. For Hevesy's autobiography and his history of the discovery of hafnium.