Includes letters to Spiegelberg from: Marvin Farber, Department of Philosophy, The University of Buffalo, New York; Helmut Kuhn, Department of Philosophy, Emory University, Atlanta, Georgia. Includes letters from Spiegelberg to: Marvin Farber, Department of Philosophy, The University of Buffalo, New York. Includes letters to Helmut Kuhn, Department of Philosophy, Emory; University, Atlanta, Georgia from: Marvin Farber, Department of Philosophy, The University of Buffalo, New York; Cornelius Kruse, American Council of Learned Societies, Washington D.C.; Helmut Kuhn, Department of Philosophy, Emory University, Atlanta, Georgia to: Marvin Farber, Department of Philosophy, The University of Buffalo, New York.