The collection consists of correspondence, manuscripts, and ephemera by and relating to John Steinbeck collected by Preston Beyer. Included is a large amount of correspondence (circa 1939-1993) of Beyer with bibliographers, critics, collectors, biographers, universities, friends, and relatives concerned with the life and works of John Steinbeck. Some of these correspondents are Gwendolyn and Elaine Steinbeck (former wife and widow, respectively), Carlton Sheffield (Steinbeck's roommate at Stanford), John Hargraves, Adrian H. Goldstone, Robert J. Demott, John Ditsky, Warren G. French, author of John Steinbeck's Fiction Revisited (1994), Tetsumaro Hayashi, author a A New Steinbeck Bibliography, 1971-1981 (1983), Roy S. Simmonds, Nelson Valjean, and Robert Wallsten, editor, with Elaine Steinbeck, of Steinbeck: A Life in Letters (1994). Also present is correspondence with university libraries containing collections of Steinbeck books and manuscripts, such as San Jose State University and Ball State University.

Original Steinbeck material includes 27 cards and letters (1951-1967), some written by his secretaries, to Lemuel and Shirley Ayers, Preston Beyer, Mary Bradford, one to Martin Luther King (March 31, 1965), June Hunderson, and a few others. In addition, there is a photograph (1962) of Steinbeck taken by Carlton Sheffield, a three-page, typed, signed article entitled "Rationale," and a signed copy of his Nobel Prize acceptance speech (1962). Related materials include a holograph review (1939) by George Stevens of Steinbeck's Uncovered Wagon, and a script (1954) for a dance-drama adaptation by John H. Jones of Steinbeck's The Pearl. Also included are 13 photographs from the 1992 John Steinbeck Conference in Nantucket, as well as other Steinbeck Society events.