Correspondence, memoranda, legal briefs and case files, reports, financial records, scrapbook, printed matter, maps, photographs and other papers documenting Thayer's legal career in private practice in New York City and as a district attorney for New York County, political activities in the Republican party, service in naval intelligence during World War II, and as assistant secretary for cultural and educational affairs at the U.S. State Dept. Topics include U.S. and Canadian bankruptcy laws; the Lindbergh kidnapping case (as assistant counsel to Charles A. Lindbergh); his support of Thomas E. Dewey's campaigns for New York City, New York state, and national offices; Unesco and other international congresses; and art in U.S. embassies. Correspondents include McGeorge Bundy, William R. Castle, Thomas E. Dewey, C. Douglas Dillon, William J. Donovan, Allen Welsh Dulles, John Foster Dulles, Sol Hurok, Dean Rusk, and Sinclair Weeks.