The Marx Papers (MC 8) consist of six correspondences that span the years 1905-1913. All but one of the letters is in German, with the remaining one, Curie’s in French. The correspondence in the collection are Svante Arrhenius (Nobel Prize, 1903, for his research on cathode rays); Marie Curie (Nobel Prize, 1911, for her discovery of radium and polonium and the isolation of radium); Phillip Lenard (Nobel Prize, 1905, for his research on cathode rays); Hendrik Lorentz (Nobel Prize, 1902, for his investigation of the influence of magnetism on the phenomena of radiation); Wilhelm Ostwald (Nobel Prize, 1909, for his pioneer work on catalysts, chemical equilibrium and reaction velocities); and Max Planck (Nobel Prize, 1918, for his discovery of the elemental quanta). While each of these letters is significant due to the fact that each correspondent is a Nobel Prize winning scientist, three of the letters have special significance due to Marx’s early personal association with the writers. As an undergraduate, Marx studied theoretical physics with Max Planck, from 1898-99 Marx was Assistant to Phillip Lenard at the University of Kiel, and from 1900-01 Marx was involved in research with Svante Arrhenius at the University of Stockholm. English translations are available for all correspondence.