This subseries contains mostly research files of Counterattackon organizations that Counterattack viewed as possible Communist Party fronts, the bulk of which were collected in the 1940s. Much of the activity of the Communist Party took place in the context of working within mass organizations; those established by the Party were often referred to as front organizations. Mass organizations were usually devoted to a single issue or constituency and had a broader membership and political appeal than that of the official Party line. Some organizations within this series were known fronts, others were suspected fronts by ABC. The materials in this subseries afford a perspective of both anti-Communist efforts to expose front organizations as well as the leftist political agenda of these alleged fronts in terms of postwar domestic and foreign policy.

These organizations are mostly left organizations, including peace movements, political action and labor committees, progressive and civil rights groups, student organizations, schools and universities, and anti-fascist groups, including the Veterans of the Abraham Lincoln Brigade and other Spanish solidarity groups. The series also features multiple Communist country solidarity groups, including the National Council for American-Soviet Friendship. Documentation within each file is essentially an accumulation of information relating to certain suspected front organizations. Materials in the collection generally consist of newspaper clippings relating to the front's activities; pamphlets and other materials published by the front organization; leaflets, programs, and announcements of front rallies, meetings, and functions; and membership lists of fronts, including names and addresses. Counterattack gathered any information they could to build a case and prove that they were Communist affiliated. There are some correspondence between organization and the editors of Counterattack, in response to Communist accusations.

This subseries contains the research files of Counterattack on trade unions suspected of being controlled or influenced by Communists. The majority of the materials come from between 1946 and 1949, and reflect attacks on Communism in unions and the attempts of union leaders to defend themselves, as well as simple documentation of union actions.

Counterattack acquired any information they could to build a case against a trade union and accuse them of having Communist sympathies in their publication or in their reports. They acquired information often through the use of mailing lists or through an informant. Files contain clippings, circulars, flyers, pamphlets, meeting minutes, membership lists, convention proceedings, and other material created by unions. The series also contains reports and internal correspondence created by Counterattack informants within the unions and the Counterattack research department. Most files are on American trade unions, many affiliated with the CIO and the AFL. Industries represented by the unions include manufacturing, entertainment, electrical, machine, retail, marine, textile, and service industries. This series also contains files on the Taft-Hartley Bill. There is a fair amount of material on union in-fighting over Communist sympathy. National unions are more widely represented. Most represented locals are based in New York.

This series contains the research files of Counterattack on specific individuals, both well-known and lesser-known, many of whom ABC suspected of having Communist affiliations. Some of the individuals highlighted by Counterattack are recognized in the film and television industry or known for their work as musicians, authors, politicians, religious leaders, political activists, newscasters, labor leaders, Communist Party leaders, or academics. The research files primarily consist of newspaper and magazine clippings, usually with names underlined or otherwise annotated, and Counterattack's internal reports on alleged Communists (though there are also some reports Counterattack prepared for outside parties). This series is also comprised of Counterattack's internal correspondence, as well as collected flyers, pamphlets, publications, and circulars, including materials created by the Communist Party.

To a much lesser extent, this series contains letters written to Theodore C. Kirkpatrick, Counterattack's managing editor, often with requests to research specific individuals. There are also several indexes which list references to individuals in other series of the Counterattack research files in this collection. Some of the indexes include references to the listed individuals in left-wing publications like The Daily Worker or Soviet Russia Today, in New York-based news sources such as the New York Times and the New York Herald Tribune, or in the reports on suspected subversive individuals compiled by Senator Jack B. Tenney, the chairman of the California Senate Factfinding Subcommittee on Un-American Activities. Other indexes include references to the individuals in this series in Appendix IX, a seven-volume compilation of names of people who participated in alleged Communist front organizations between 1930 and 1944, prepared for the House Un-American Activities Commission by J.B. Matthews and Benjamin Mandel. Some of the internal reports within this series are duplicated in Subseries VIII.