Friedrich Adler papers: Period 1879-1939: correspondence 1899-1918, including a letter by Ernst Mach 1913 and photocopies of letters by Adler from prison; correspondence with Oscar Pollak and many others 1919-1939; personal documents 1890-1952; manuscripts of his pamphlet `Die materialistische Geschichtsauffassung und ihr Verhältnis zur Ethik' 1898; letters and documents concerning the trial for his murder of Stürgkh, his apology speech and press clippings 1912, 1914-1917; file on the International Socialist Conference in Brussels 1914 and Stockholm 1917; manuscripts by others and printed material. Period 1940-1960: Personal papers 1940-1960: correspondence, including a letter by Albert Einstein 1945; notes on historical research from the fifties; manuscripts of speeches and some articles, including `Zur Geschichte des Scheiterns der Arbeiter Internationale' n.d.; album in memory of his 75th birthday 1954. Auslandsvertretung der oesterreichischen Sozialisten (AVOES) and the Austrian Labor Committee (ALC): records 1940-1945, consisting of documents relating to meetings; correspondence with Julius Braunthal, Hugo Breitner, Wilhelm Ellenbogen, Otto Leichter, Schiller Marmorek and many others; documents mainly relating to Austrian socialists in exile and their organizations in the USA and in other countries; correspondence relating to applications for visa for the USA, Mexico and Cuba, on behalf of many persons; correspondence with, and documents relating to American authorities and other organizations, including the Jewish Labor Committee (JLC) and the Club der Österreichischen Sozialisten. Kathia Adler papers: correspondence with Rafail Abramovič 1960, Annie Adama van Scheltema-Kleefstra 1955-1965, Julius and Tini Braunthal 1956-1966, Fedor and Lidija Dan 1931-1960, Otto Leichter 1945-1965, Oscar and Marianne Pollak 1923-1963 and others 1899-1966; family correspondence with Friedrich Adler 1899-1959, with her children Alice, Emmi and Felix Adler 1912-1966 and other relatives 1902-1935; personal documents 1894-1951. NB. Part of the Friedrich Adler papers at the Verein für Geschichte der Arbeiterbewegung in Vienna, Austria.