Professional and personal files including Armstrong's correspondence with professional associations, other engineers, and friends, his research notes, circuit diagrams, lectures, articles, legal papers, and other related materials. Of his many inventions and developments, the most important are: 1) the regenerative or feedback circuit, 1912, the first amplified radio reception, 2) the superheterodyne circuit, 1918, the basis of modern radio and radar, 3) superregeneration, 1922, a very simple, high-power receiver now used in emergency mobile service, and 4) frequency modulation - FM, 1933, static-free radio reception of high fidelity. More than half the files concern his many lawsuits, primarily with Radio Corporation of America, over infringement of the Armstrong patents. Litigation continued until 1967. Other files deal with his work in the Marcellus Hartley Research Laboratory at Columbia University, 1913-1935, and with the American Expeditionary Forces in France during World War I, his Air Force contracts for communications development, Army research during World War II, the Radio Club of America, the Institute of Radio Engineers, FM development at his radio station at Alpine, N.J., the use of FM in television, his involvement in Federal Communications Commission hearings and legislation, and his work with the Zenith Radio Corporation. Also, letters to H.J. Round

The correspondence, research, and teaching files of French-American cultural historian and Columbia University professor emeritus Jacques Barzun (1907-2012).

Correspondence, manuscripts, notes, documents, book typescripts, photographs, and printed materials covering the time from Dorfman's early interest, as a graduate student, in the economic thought of Thorstein Veblen until his retirement. There is correspondence with his academic colleagues, students, publishers, and the family and students of Thorstein Veblen, as well as manuscripts, typescripts, drafts, revisions, notes, photographs, pamphlets, and related materials for his articles and books which include: THORSTEIN VEBLEN AND HIS AMERICA, 1934; THE ECONOMIC MIND IN AMERICAN CIVILIZATION, 1946-1959; EARLY AMERICAN POLICY, 1960; INSTITUTIONAL ECONOMICS, 1963; TYPES OF ECONOMIC THEORY, 1967; and NEW LIGHT ON VEBLEN, 1973

Correspondence, playscripts, screenplays, scenarios, short stories, and other manuscripts, drafts, photocopies, contracts and other documents, tearsheets, clippings, and other materials relating to his career as a screenwriter, playwright, and author of short stories. Correspondence with friends, students, admirers, and professional colleagues concern his teaching, playwriting, films, articles, photography, and literary topics. There are also two groups of letters from students and readers about his textbook, "The Human Nature of Playwriting" (1949). Among the cataloged correspondence are William Gibson, MacKinlay Kantor, Anna Louise Strong, Louis Untermeyer, and Carl Van Doren. Included are manuscripts, drafts, or photocopies of almost all his films, plays, and short stories, such as playscripts and drafts of his plays, "The Jazz Singer" (1922), "Skylark" (1939), "Jason" (1942), and others; screenplays and scenarios, many in photocopy, of "Trouble in Paradise" (1932), "The Merry Widow" (1934), "The Shop Aroung the Corner" (1940), "Suspicion" (1941), "Heaven Can Wait" (1943), and many other films; and manuscripts, drafts, tearsheets, and printed copies of his short stories and articles of film and television criticism. There are also many clippings and reviews, programs, and other printed materials about his plays and films.

Correspondence, manuscripts, documents, financial records, photographs, memorabilia, and printed materials. The Foundation's correspondence files consist of letters from different organizations and foundations, including the Martin Luther King, Jr. Center for Social Change, The NAACP, the United Negro College Fund, the Studio Museum in Harlem, and the YWCA. Also included in this collection are community dialogues on race relations (1974-1975); proposed dialogues (1979) on such subjects as the Boy Scouts of America, Columbia University, and the National Council of Christians and Jews; and files on the Whitney M. Young Fellows Retreat Conferences (1980-1984). The collection contains many files on Ed Wilson's bust of Young (1991), including contracts and agreements, records of payments to Wilson, documents concerning the bust's placement in various locations, correspondence with Wilson (1983-1991), and miscellaneous photographs and pictures. The contributions files contain annual listings of contributions and records of contributions from the National Urban League, assorted organizations, corporations, individuals, foundations, and Philip Morris.