An intelligent, thorough opera-by-opera study which seriously suffers, however, by comparison with William Mann's The Operas of Mozart (1977). The two volumes adopt identical formats: each chapter begins with biographical background and notes on the creation of the libretto and score in question, then moves on to a scene-by-scene, aria-by-aria musical and dramatic analysis. Osborne does furnish a bit more biographical detail and continuity than Mann. And occasionally his concern for dramatic values and his avoidance of extensive musicology give his discussion a more down-to-earth quality. But down-to-earthness is hardly the essence of Mozart, and Osborne's efficient and dispassionate job rarely can rival Mann's exuberant and richly detailed evocations of the music and its emotional impact. Osborne's writing on opera is never less than thoughtful and knowledgeable--he achieves his own sort of exuberance in his books on Verdi--and the scholar or buff will want to have his perceptions alongside those of Mann and E. J. Dent and Alfred Einstein. But if only one study must serve, it must be Mann's far longer, far more committed and stimulating volume.