Central Files is composed chiefly of correspondence sent and received between Columbia University administrators and other University officers, faculty, and trustees, as well as correspondence sent and received between University administrators and individuals and organizations from outside the university.

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

Correspondence, manuscripts, notes, documents, subject files, photographs, art works, and printed materials. This collection covers the entire span of his life, although by far the greatest part relates to his activities as a professor from the 1930s to the 1960s. Among the correspondents are many important figures in American Russian studies or Columbia University; there are also many letters from his wife, Clemens T. Robinson, and Lewis Mumford. Manuscripts by Robinson include his "Rural Russia under the Old Regime" lectures, notes, speeches and essays, and also miscellaneous pieces (essays, reviews, poems, stories, plays, etc.) that he wrote while he was an aspiring young journalist and writer in the 1910s and 1920s. Manuscripts by others consist of student theses, papers, books and reports that were given him for review or comment. Subject files deal with such topics as his service in World War I; Columbia University (especially the Libraries and the History Department); and various aspects of academic life and Russian studies. Almost nothing in the collection has any bearing on his government service during World War II; items from the war years concern personal affairs or scholarship. There are photographs of Robinson and his wife; family photographs from the late 19th and early 20th centuries; and Russian scenes. Art works include items by Clemens T. Robinson. Among the printed materials are two books inscribed by Mumford to Robinson.

The materials that comprise the Historical Biographical Files have been collected and added to from a variety of sources over the years by current and previous staff. The files consist of materials related to people who have a connection to the University whether as student, alumni, administrator, faculty, staff, guest lecturer, or honorary degree recipient. Materials generally consist of newspaper and magazine clippings, press releases, programs, ephemera, printed matter, lists, reports, and pamphlets.

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 Morningside Area Alliance is an organization working for community improvement on behalf of its member institutions in the Morningside Heights neighborhood in New York City. The organization was founded as Morningside Heights Inc. in 1947 through joint action of fourteen Morningside Institutions--Columbia University, St. Luke's Hospital, Cathedral Church of St. John the Divine, Teacher's College, Barnard College, Corpus Christi Church, Home for Old Men and Aged Couples, International House, Jewish Theological Seminary, Juilliard School of Music, St. Hilda's and St. Hugh's School, The Riverside Church, Union Theological Seminary, and the Women's Hospital of St. Luke's Center--with the expressed purpose of "[promoting] the improvement of Morningside Heights as an attractive, residential, educational, and cultural area." The collection includes much, if not all, of the material that was created by the organization as part of its daily business from 1947 to 1992, when the materials were accessioned into University Archives at Columbia University. This includes records of the Board of Directors and the various Committees within the Alliance; assorted publications, reports, pamphlets, and theses both acquired and created by the organization; files of the different offices within the organization; maps, plans, and photographs used and created by the Alliance for its work; and the collected materials and files created for the organization's projects in different subject areas--specifically buildings, community services and programs, public safety, schools, and the Morningside General Neighborhood Renewal Plan. The collection also includes a large quantity of material rearranged into subject files on different areas of concern within the organization.

Correspondence, memoranda, photographs, manuscripts, lists, legal and financial documents, and printed materials of Simon. The personal and business papers include correspondence with authors, inscribed photographs of authors, editorial files, files for his special art, photography, and music projects, correspondence files relating to Simon and Schuster, Inc., personal and family correspondence, documents, and photographs. Correspondents include Irving Berlin, Margaret Bourke-White, Henri Cartier-Bresson, Joseph E. Davies, Dwight D. Eisenhower, Philippe Halsman, Jerome Kern, Cole Porter, Kenneth Roberts, Arthur Schnitzler, Jerome Weidman, and Sloan Wilson.

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.