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.

This collection contains the personal and professional papers of Abraham Liessin, including correspondence with many important literary figures, manuscripts of essays and poems by Liessin from Di Tsukunft(The Future) and from his published works, clippings, receipts, invitations, and other materials relating to Liessin’s family. This collection shows how Di Tsukunft became one of the leading Yiddish literary journsl during hte 25 years of Liessin's editorship.

This collection contains documents relating to Isaac A. Hourwich’s role as an economist, publicist, statistician, lawyer, author, and authority on immigration, as well as his involvement with the labor movement and the formation of the American Jewish Congress. There are reports, minutes of meetings, memoranda, clippings and correspondence, and manuscripts and articles about Jewish labor, Socialism, Russia, Marxism, immigration, and other subjects. These materials demonstrate Hourwich’s important role in American labor, immigration theory, and political and economic theory.

This collection contains documents of journalist and left-wing political activist Paul Novick, consisting mainly of correspondence, subject files, manuscripts, photographs, and newspaper clippings. These materials relate to Novick’s career as long-time editor of the Morning Freiheit (Morning Freedom), his important role in the worldwide Communist movement, the history of the Freiheit itself, and Jewish and general politics. These materials demonstrate Novick’s important, and changing, role in the history of Communism, as well as his career as a Yiddish journalist and author.

This collection contains the personal and professional papers of Shmuel Mordkhe Zygielbojm, a Jewish-Polish Socialist politician, Bund leader, member of the National Council of the Polish Government-in-Exile in London, and a labor and political leader. These materials include Zygielbojm’s writings, personal correspondence, clippings, and some photographs. These materials relate mainly to Zygielbojm’s work in London as well as the worldwide reactions after his suicide.