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

Papers of the American author, caricaturist, illustrator, painter. Collection includes correspondence between Bacon and her husband Alexander Brook, as well as that of others; manuscript articles, illustrations, poems, and notebooks; published material including articles, drawings, and newspaper clippings by or about Bacon and Brook; memorabilia, including awards, photographs, and reviews; and miscellany.

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

These papers consist of correspondence, manuscripts, documents, subject files, photographs, and printed materials. Most of the collection concerns Bashmakov's ethnographical work in France in the 1920s and 1930s, including correspondence, many manuscripts, lectures, notes, and copies of his publications. Subject files concern emigre monarchism in France, and the death of Father Georgiĭ Spasskiĭ. There are copies of the Russian version of Bashmakova's memoirs, "Perezhitoe." Cataloged correspondence in the collection consists of letters from Petr Krasnov and one or two items each from Henry Field, Evgeniĭ Miller, Petr Wrangel, and Boris Zaĭt︠s︡ev. There are also photographic slides representing ethnographical types from the Caucasus.

More than one thousand photographs of 19th century sideshows and circuses, most by photographer Charles Eisenmann or his successor Frank Wendt, the remainder by unknown photographers. Most of the photographs depict the physical abnormalities of humans and animals featured at these shows. Subjects include P.T. Barnum, the P.T. Barnum Firm (Barnum and Bailey Circus), and Tom Thumb. Also included are Becker's research notes, an 1865-1868 run of The New York Clipper (forerunner of Billboard Magazine), and various print (broadsides and posters) and non-print circus memorabilia.

The collection consists largely of printed materials (clippings and offprints), concerning the prehistory of the Middle East, Russia, and Europe. There are also some notes, texts of lectures, and a few letters.

Correspondence, manuscripts of poems, and manuscripts of lectures by Benjamin. The correspondence consists of original letters of Benjamin, typescript and photostatic copies of Benjamin letters in other libraries, and letters to Benjamin from some of his literary contemporaries including Paul Hamilton Hayne, Willis Gaylord Clark, John Lothrop Motley, and Fitz-Greene Halleck. Many of the letters relate to Park Benjamin's lecture tours. There are other family letters and many documents relating to the Benjamin family,and two letterbooks of John Lothrop Motley. Also, a large amount of genealogical material of the Benjamin family, and its related families from the 16th century to the present day. There are also financial records, monographs, clippings, and photographs.

Correspondence, manuscripts, notes, and printed materials of Georgiĭ P. Benningsen, brother of E.P. Benningsen and, in the emigration, an associate of Vladimir Burt︠s︡ev. Much of the correspondence consists of letters to Georgiĭ Benningsen by Burt︠s︡ev (69 letters from the 1920s). Manuscripts include Benningsen's memoirs about Burt︠s︡ev, copies of Burt︠s︡ev's (apparently published) memoirs, and notes. Printed materials are chiefly clippings on various topics. There are also scattered issues of 1917 Russian newspapers ("Nash Vek," "Russkoe Slovo"), and an autographed copy of Burt︠s︡ev's 1919 edition of Griboedov's "Gore ot uma."

The papers consist of correspondence, manuscripts, documents, original art works, bibliographic notes and material on exhibitions. There are letters from Aleksandr Benois, Mikhail Chekhov, Fedor Komissarzhevskiĭ, Georgiĭ Lukomskiĭ, Nikolaĭ Medtner, Vladimir Nabokov and Aleksandra Tolstai︠a︡, and one letter each from Ivan Bunin, Mikhail Fokin, Tyrone Guthrie, Sok Hurok and Serge Kusevit︠s︡kiĭ. The manuscripts include essays by Dobuzhinskiĭ on such topics as the Mir Iskusstva group, Pushkin's illustrations, Aleksandr Blok, Kuzḿa Petrov-Vodkin and Josʹe-Maria Sert. There are original art works (pen and ink, goache, etc.) relating to his artistic and theatrical productions. Also included are photographs of Russian scenes, apparently from before World War I.

Correspondence, manuscripts, papers, essays, etc. relating to Berlioz, and 19th century arts and literature. The correspondence includes original Berlioz letters and over 200 copies of letters relating to Berlioz and the romantic era, written by musicians, critics, historians, and literateurs of the past century. There are many photostats of letters and manuscripts obtained from the principal libraries of the world which hold original Berlioz material. The collection includes much printed material in the form of music scores, published letters, essays, clippings, biographies, music and book catalogues, program notes, and playbills.