Series I: Alger Hiss Materials, 1948-1994, contains correspondence with Alger, Isabel and Tony Hiss, correspondence regarding Whittaker Chambers, and other correspondence between Reuben and scholars, journalists, research assistants and others interested in the Hiss Case. The collection also includes research materials pertaining to the Hiss Case. Note: Series I. Alger Hiss Materials, 1948-1994 was microfilmed as part of the collection, "Alger Hiss Papers at the Tamiment Library," (Thomson Gale Publishers). NOTE: Researchers should use the microfilm (R-7771E).

Series II: Subject Files, 1923-2003, consists primarily of material gathered in the course of Reuben's research on Alger Hiss and Whittaker Chambers, including Edward H. Fearon's trial evidence regarding the Hiss family's Woodstock typewriter, files on the history of espionage, legal records pertaining to Reuben's and Hiss's attempts to obtain the release of government documents, and several drafts of Reuben's unpublished manuscripts on Hiss and Chambers..

Series III: Files Obtained under the Freedom of Information Act (FOIA), 1930s-1970s. Most of these materials were obtained by attorney Victor Rabinowitz in response to his FOIA requests and litigation on behalf of Alger Hiss and/or William Reuben. The series also contains redacted FBI and other government files collected by William Reuben during his research for the Hiss and Chambers manuscripts.

Series IV: Note Cards, Undated. One box of handwritten and typed note cards relating to individuals and subjects of interest to Reuben for his research for the Hiss and Chambers manuscripts, as well as notes for other research projects and articles.

Series V: Audio Cassettes, 1948-1996. This series contains 46 audiotapes including 30 cassette tapes and sixteen micro-cassettes. Eighteen of the cassette tapes are identified as being interviews and radio programs collected by William Reuben, including Reuben presenting at the University of New York, Paul Berman interviewing Ronald Radosh and presentations by Sender Garlin and Michael Parenti at the University of Colorado; twelve of the cassette tapes are unlabelled. Nine micro-cassettes are labeled as containing interviews Reuben conducted with Raisha Vasilievna and Professors Dubovsky and Goldvin in Moscow, and with Grete Fuchs in Dresden; seven of the micro-cassettes are unlabeled.

Series VI: U.S.A. v. Alger Hiss, 1949. This box of court transcripts from Alger Hiss's first trial consists of copies of material also found in the John Lowenthal Papers (Tamiment #190).