Nearly 1300 letters arranged alphabetically by surname, with letters received on the announcement of his knighthood in a separate file at the end, followed by a file of letters from unidentified correspondents. Other correspondence relating directly to various plays may be found in the Works series under the title of the play. Shaffer did not use email but printed emails provided by friends and agents may be found in the collection. Denis Zaphiro's letters are the earliest dated letters, beginning in 1944; some of them are addressed to both Peter and Tony Shaffer.
Correspondents include members of the Shaffer family, and friends from St Paul's School: James Mossman, Jerrold Weinstein and Denis Zaphiro, Trinity College friends Mal Diamond, Donald Friedman, Raymond Leppard, Richard Mayne (also at St Paul's with Shaffer), and Leopold de Rothschild. Shaffer's letters to his parents, and also to Jerrold Weinstein appear in the archive, as they were passed to Shaffer following the deaths of his parents and after Weinstein's early death. There are also letters from Shaffer's long time partner Robert Leonard, as well as colleagues from the theatre and performance arts including Leonard Bernstein, Simon Callow, Paul Giovanni, John Gielgud, Peter Hall, Harold Pinter, Stephen Sondheim, Victor Spinetti, and Tom Stoppard.
Two letters include parts of letters written by Peter Shaffer: a letter from Elizabeth Cavendish, 29th September 1974 (C42) and a typed letter from Costas Gianakaris 27 Sept. 2014 (G6) which includes the draft of a love letter[?] on the back of the second sheet.