A series of correspondence including Sassoon's incoming and outgoing correspondence, as well as letters received by various relatives. The letters to Sassoon include a large set from his mother, Theresa Sassoon, along with letters from Sir Edmund Gosse, Edith Olivier and Laurence Whistler, among others. The letters from Sassoon include letters to his wife Hester, to the bookseller, H.P Muir, and a number to his mother. Some of the letters to Hester Sassoon are illustrated. Max Egremont also collected letters received by Sassoon's relatives. The letters to Theresa Sassoon include a number received from Siegfried's brother Hamo Sassoon, dating from the First World War, together with letters received following his death in action in 1915, including two letters from Siegfried Sassoon. The letters to Hester Sassoon include one from Edmund Blunden.