Barghoorn's Professional Files (1.5 linear feet) are arranged alphabetically and include correspondence; materials on grants and funding agencies; various professional organizations and conferences files; and writings, including book reviews and book chapters. The correspondence is divided into several chronological sections. Within each section letters are arranged alphabetically by the last name of Barghoorn's correspondent. There is also a folder of the correspondence between Barghoorn and his former student, Ellen Mickiewicz. The bulk of the correspondence consists of outgoing letters from Barghoorn, chiefly to professional colleagues in academia and government, discussing his and others' work in Soviet studies. There is little mention of his arrest by the Soviet government in 1963, except for a brief summary of the incident in a letter to Pat Briggs dated 1965 November 10. Other letters concern collaborative projects, funding opportunities, and departmental and university matters. A few items mention student unrest at Yale in the spring of 1970.