This collection contains materials collected by David Trotsky relating to the Jewish community of Belgium in the inter-war period. Materials include printed documents, posters, reports, meeting minutes, and newspaper clippings, mainly pertaining to the Jews of Brussels and Antwerp.

The collection contains play manuscripts, programs, playbills, posters, photographs, correspondence, agreements, scrapbooks, clippings, printed ephemera, and memorabilia relating to Yiddish theater primarily in the early twentieth century, especially the interwar period. Also included are items of printed ephemera related to Yiddish film, Hebrew theater, and a broad range of Jewish performers, including cantors, singers and dancers. Geographically, the materials originate predominantly in Poland and other parts of Eastern Europe, including parts of the Russian Empire and, later, the Soviet Union; and, to a lesser extent, the United States, especially New York City. Also included are materials from Western Europe, Palestine (Eretz Israel), South America, and other regions around the world. Among the theater personalities represented in the collection with significant amounts of material are Herz Grossbard, David Herman, Joseph Winogradoff, Rudolf Zaslavsky, Zygmunt Turkow, Jonas Turkow, Moyshe Lipman, Ida Kaminska, and Esther Rachel Kaminska. The theater groups best represented include the Varshever Yidisher Kunst-Teater (VYKT; Warsaw Yiddish Art Theater), founded by Zygmunt Turkow and Ida Kaminska; the Vilna Troupe; Yung Teater / Nay Teater (Warsaw; Vilna), under the direction of Michael Weichert; the Moscow State Yiddish Theater (known by its Russian acronym "GOSET"); Maurice Schwartz's Yiddish Art Theatre, of New York; and the Hebrew theater "Habimah." A wide variety of other professional as well as amateur theater groups are represented with smaller amounts of material.

This collection contains correspondence, pamphlets, periodicals, newspapers, press releases, writings, clippings, brochures, fliers, and posters from the era of the Spanish Civil War, and later, documenting American and international fund-raising for humanitarian relief of Republican Spain; American and international public opinion about the war; the participation of Jews in the International Brigades; and reminiscences and commemorations of the war and, particularly, of the International Brigades, in later years. A portion of the material on relief work pertains to trade union activities, as documented in papers of Charles S. Zimmerman, of the International Ladies’ Garment Workers’ Union, in his capacity as leader of Trade Union Relief for Spain, in New York City. Other organizations represented include the Medical Bureau and North American Committee to Aid Spanish Democracy; the Spanish Information Bureau in New York; the Friends of the Abraham Lincoln Brigade; and the Israeli branch of the association of volunteers in the International Brigades. There are also autobiographical manuscripts by Benjamin Lubelski and Sigmund Stein, who participated in the International Brigades; and contemporary publications in a variety of languages, including publications of the anarchist-leaning Spanish trade union confederations CNT-FAI.