"Correspondents include librettists William Plomer (Gloriana) and Myfanwy Piper (The Turn of the Screw), and friends and collaborators such as Edith Sitwell, E. M. Forster, Basil Coleman, Imogen Holst, Francis Poulenc, Lennox Berkeley, the Earl of Harewood and Britten's partner and principal interpreter, Peter Pears." . . . . . . .