Interpretive criticism applied to the plays of W. S. Gilbert verges upon self-parody, suggests Eric Midwinter. The musical plays to which Sullivan contributed his inimitable scores were careful and calculated blends of the theatrical resources which Gilbert could command with plot and character conventions of proven and sustained appeal – which could, moreover, attract to the theatre the respectable family audiences for which the Savoy became almost a home-from-home. Eric Midwinter analyzes the ingredients of the operas which contributed to this popular success, describes the veritable industry of spin-offs which they generated, and assesses their contribution to the development of the ‘musical play’ as distinct from the ‘musical comedy’. Eric Midwinter is a social historian and social policy analyst, whose books include Make 'Em Laugh: Famous Comedians and Their World (1979) and Fair Game: Myth and Reality in Sport (1986). He has published widely on social aspects of popular theatre and television, and is presently Director of the Centre for Policy on Ageing.