From the accessioned cassette sleeve:

In researching for my book Reinhold Niebuhr and John Dewey: An American Odyssey (Albany, SUNY Press, 1973) Sidney Hook granted me this interview. On June 17, 1986. The first few seconds were not recorded. Follow-up questions of mine were answered by mail. Copies of my letter of August 14, 1986 and Professor Hook's August 27, 1986 reply are enclosed.