This book aspires to be at once a guide to the world of opera, prepared under the auspices of the Metropolitan Opera Guild (a "Metropolitan Opera Encyclopedia"), and a compendium of information specifically related to the Metropolitan Opera, its history, repertory, and performers (a "Metropolitan Opera Encyclopedia"). While intended to answer a wide range of questions about this international art form, its composers and librettists and their works, its singers and conductors, designers and producers, its terms and the places where it has been most notably practiced, the book also offers, where appropriate, greater detail about their Met-related aspects (and, as the first such book compiled in the United States in some years, also a more generally American focus). Obviously, the constraints of space prevent it from completely fulfilling these dual roles, but we hope that the result will prove useful to all operagoers and listeners, not only to the millions who attend the Met or share in its performances through radio and television.