Personal, academic, and legal correspondence, manuscripts, documents, photographs, and memoranda. Among the legal files, there is particular emphasis on labor and welfare law. The files also contain materials about his judicial appointment, the American Law Institute, the Columbia University School of Law, and the Project on International Procedure. Among the major correspondents are: James A. Farley, Arthur J. Goldberg, Philip C. Jessup, Robert F. Kennedy, Harold R. Medina, James A. Pike, and Lionel Trilling

Correspondence, writings, reports, memoranda, case files, and related printed materials. The papers cover the entire field of law with particular emphasis on civil rights, labor law, and family law. They include several series of office files dealing with Columbia University Law faculty, students, his course materials, and the administration of the Law School. In addition, there are numerous files for Amherst College (from which Gellhorn received his A.B. degree), arbitration cases, federal administrative procedure, legislation, the American Civil Liberties Union, the Association of American Law Schools, and Fordham University (for which he prepared a study). There are manuscripts, drafts, proofs, correspondence, and other related materials for some of his books: Administrative Law Cases and Comments (1940); Security, Loyalty and Science (1950); The States and Subversion (1952); Individual Freedom and Government Restraint (1956); When Americans Complain (1966); and Ombudsmen and others (1966).