The third volume of Coward's plays contains some of his best work from the thirties. Design for Living - is about a triangular alliance between two men and a woman, based on friends of Coward's, which he waited to write ''until she and he and I had arrived by different roads in our careers at a time and a place when we felt we could all three play together with a more or less equal degree of success.'' Cavalcade was Coward's most ambitious stage project, set during the Boer War, which cost GBP30,000 in its day and which includes scenes of the relief of the sinking of the Titanic and the coming of the Jazz Age. Conversation Piece is a musical comedy that Noel wrote for the Parisian star Yvonne Printemps and includes the song ''I'll Follow My Secret Heart''. Also in the volume are three short plays including Tonight at 8.30 - Hands Across the Sea, a gentle satire of colonials and London Society; Still Life which became the film Brief Encounter and Fumed Oak a suburban comedy about a 'worm who turns'. The volume is introduced by Sheridan Morley.