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 collection consiste of correspondence, memoranda, reports, bulletins, clippings, photographs, awards, and printed material. The files, arranged by genre and topic and reflect her philanthropic and legislative work in the areas of health, specifically cancer, heart disease, and mental health. Her civic and legislative work is covered in detail, as well as her private interests and activities.

Personal and professional correspondence, including 25 long letters from Professor Henry F. Herbig; manuscripts (mainly speeches); specifications for patents in electrical fields; technical and personal photographs; and memorabilia. Included is a copy of the famous "shot in hand" x-ray photograph, ca. 1896, one of the first ever to be taken. This collection also contains the correspondence, manuscripts, documents, and memorabilia of Professor Pupin's daughter, Varvara Smith, and his son-in-law, Louis Graham Smith. His daughter's letters and documents deal with her financial difficulties, her administration of Pupin's estate and her claims against Columbia University. Louis G. Smith's letters deal with his anti-Communist sentiments and his manuscripts are mainly ideas for popular songs and plays. There are three letters (photostatic copies) to Smith from Dwight D. Eisenhower.

The V. K. Wellington Koo papers document the diplomatic legacy of Wellington Koo as a Chinese statesman and diplomat of the 20th Century. The papers primarily consist of materials collected during Koo's diplomatic career, relating to the Lytton Commission, 1932-1933; the League of Nations, 1931-1940; the United Nations, 1944-1946; his ambassadorships to France, 1932-1941; to Britain, 1941-1946; to the United States, 1946-1956; as the Senior Advisor to the Republic of China from 1956; and as the Judge on the International Court of Justice, 1957-1966. The materials include correspondence, diaries, memoranda, manuscripts, documents, notes, speeches, maps, photographs, printed material, and audio visual material. The bulk of the materials emphasizes China's domestic and foreign affairs, such as the Sino-Japanese conflict, World War II and the Cold War in the Far East region, as well as the League of Nations and the United Nations.