The collection consists primarily of letters to Raymond Mortimer, but also includes notebooks, drafts of reviews, photographs and albums, and miscellaneous printed ephemera. The Bloomsbury group is well represented with letters by Vanessa and Clive Bell, Virginia and Leonard Woolf, Lytton Strachey, Maynard Keynes, Desmond and Molly MacCarthy, Roger Fry, and Duncan Grant. There are long series of letters from Harold Nicolson, Vincent "Jimmy" Sheean, and Nancy Mitford. The correspondence concerns literary allusions and criticism, but also social commentary and gossip. Many of the letters, such as those from Rebecca West, also contain references to family matters.

Also included in this collection are photographs of Mortimer, from his youth to old age. Several of the photographs are with friends, such as Clive Bell, Harold Nicolson, and Edward Sackville-West. Photograph albums date from 1905-1919; many of the pictures show the French hospital where Mortimer worked during the war. In addition, there are notebooks and diaries containing early verse, Oxford essays, a manuscript fragment of a novel, stories, and an extensive account of a visit to Italy (circa 1920).

The following standard abbreviations, or their variations, are used to identify materials in this collection: ALS = autograph letter signed, TLS = typed letter signed, ACS = autograph card signed, TCS = typed card signed, ANS = autograph note signed, TNS = typed note signed, AMsS = autograph manuscript signed, and TMsS = typed manuscript signed.