The correspondence files span a period of over 70 years, with the bulk of the correspondence dating from the years 1933-1976. The correspondence has been arranged alphabetically within several categories: family, professional and general, students, politicians and public officials (U.S. and Germany), administrative and faculty members of the New School for Social Research, and organizational correspondence. The professional and general correspondence includes substantial amounts between Brecht and Julie Braun-Vogelstein, Jürgen Fehling, Carl Joachim (Achim) Friedrich, Kurt von Fritz, Ernest Hamburger, Ernest Hocking, Fritz Morstein-Marx and Gustav and Lydia Radbruch, as well as with former students Morris Forkosch and Alfred J. Jung. The collection also contains correspondence with the American statesman John Foster Dulles, as well as lengthy exchanges with German statesmen Otto Braun, Heinrich Brüning, Ferdinand Friedensburg and Theodor Heuss. The series also contains Brecht's correspondence with other members of the New School for Social Research, most notably with former New School Deans Alvin Johnson, Hans Simons and Hans Staudinger.