The 1983-1997 Accessions subgroup is divided into ten series: Calvin Cunningham case, Clippings, Correspondence, Government documents, Lake County materials, Memorial materials, Personal material, Political Organizations, Press Releases and Publicity, and Print and Broadcast Material.
The Calvin Cunningham case series (1983-1996) consists of material concerning Williams' advocacy on behalf of a death-row inmate, Calvin Cunningham. In 1991, Cunningham was convicted of murder in the 1990 shooting death of a policeman in Charlotte, North Carolina. Cunningham maintained his innocence.
The Clippings series (1957-1996) consists of clippings from American and international newspapers and magazines concerning Robert Williams.
The Correspondence series (1961-1996) covers personal and political issues. Correspondents include political allies, journalists, government officials, scholars, and friends.
The Government Document series (1951-1981) consists of material Robert Williams received from government agencies through Freedom of Information Act requests. The series is subdivided into seven subseries based on the government agency which produced the documents: FBI, CIAIRS, Michigan State Police, Federal Post Office, State Department, and Treasury Department. In some cases, the provenance of the documents was unclear. For instance, unfoldered copies of documents produced by the Michigan State Police might have been gathered and released by the FBI or CIA. Where the identity of the agency that released documents was unclear, those documents were organized by the government agency which originally produced the document. The FBI subseries is subdivided into two sub-subseries based on their system of organization. Where possible, the original filing system used by the FBI (documents are organized into numbered sections) has been preserved, and where that system was disorganized or obscured, the documents were arranged in a rough chronological order.