The materials in the collection were created and accumulated by John and Constantine Poulos. The collection contains correspondence, dispatches and articles, typescripts, political cartoons, internal documents and bulletins of left-wing organizations, government documents, pamphlets and other published materials. The bulk and richest portion of the collection documents the Greek Civil War, 1944-49, and the history of Greek Trotskyism. There is also good documentation of the period of the Greek Junta, 1967-74, and resistance thereto, and of Greek-American radicalism. The collection is organized into five series, described below. In addition, three linear feet of Greek language publications have been separated for future integration into the Library's book, serial and ephemera holdings.

Series I, Constantine Poulos' writings and correspondence, offers keen insight into the situation in Greece, 1944-49, and the reaction of Britain and the U.S. In addition to his press dispatches and published articles, there are political cartoons by Poulos, U.S. government documents, and pamphlets published in the U.S. and Britain in support of the guerilla forces. This series also documents the consequences for Poulos' journalism career of his reportage on Greece.

Series II documents the Greek Resistance and Civil War and its Aftermath. Materials include EAM-ELAS communiques and central committee documents, underground leaflets and newspapers, reports on prisoners, and Connie Poulos memoranda to the U.S. government. There are also documents of several Trotskyist organizations, Greek trade unions, and British and American intelligence reports and diplomatic papers. Also included are pamphlets on the resistance groups that were published for American mass audiences. In addition there are materials from the late 1940s to the late 1970s connected to the development of the Greek radical movement and American reaction to that development.

Series III is one of the most extensive collections on Greek Trotskyism. Much of it was collected by John Poulos in the 1970s for a projected definitive history of Greek Trotskyism. Included are materials on the Greek Archeio-Marxists, a non-Stalinist group (never part of the Third International) which originated in the late 1910s and ultimately merged with the Trotskyist groups in the late 1930s.

Series IV contains the correspondence Poulos undertook to locate the materials on Greek Trotskyism and the rest of the collection. Much of this correspondence clarifies the identity, contributions, and fates of various Greek Trotskyists in the U.S. and Greece. Among his American correspondents were Trotskyists Hugo Oehler and Albert Glotzer.

Series V contains materials on the anti-junta movement of 1967-1974. Most of this material was published in the U.S. by collectives of radicals and liberals and provides a sense of the activity within the U.S. and of the major issues at stake. Other materials deal with the struggles in Greece itself.

Series VI contains books and serials in Greek, awaiting processing and cataloging.

Series VII contains a scrapbook of clippings on the Greek Civil War from 1940-1948.