Massive, complex, and elaborate as a command performance of Aida-cum-elephants, this newest entry into the current marathon of operatic encyclopedias includes at least some information about practically every opera that has ever been produced, some that have not been, and some contrivances hardly worthy of the designation. The book is in two sections. First comes a finely detailed historic naturelle, in the usual progression of nationality, composer, period, from Perl through Britten by way of a staggeringly long list of contributors to the art form, including a rough dozen of exotic Middle Europeans whose biographies are uniformly neglected elsewhere. Second is an exhaustive compendium of production records entitled ""Annals of Performance"", alphabetically from Handel's Admeto to Leoncavallo's Zaza. A certain number of flaws are easily spotted: confusion in the name of the tenor role in L'Elisir d'amore, a slight incoherence with reference to the late beloved Leonard Warren's appearances in Simon Boccanegra, neglect of the recent exceptional production of Puccini's Trittico at City Center -- but despite these, the book has more meat on its bones than most quartets of its competitors. Tyros may quail before it, but market there will be, if rumors of the book's prodigious comprehensiveness can hurdle and outstrip the tortoise of its prosaic title.