Wagner’s Dream could have been a comedy—a This is Spinal Tap for opera. The production it documents, the Metropolitan Opera’s staging of Wagner’s 16-hour, four-opera Ring of the Nibelung cycle, is widely seen as a debacle. Director Robert Lapage, a Wagner novice but Cirque du Soleil veteran, made the centerpiece a creaking, 90,000-pound mechanical stage, which malfunctioned on Das Rheingold’s opening night and continued to cause problems for Die Walküre and Siegfried. Partway through, the Met lost both its star tenor and orchestra conductor to illness. Critics panned it—“the most witless and wasteful production in modern operatic history,” said The New Yorker. Met General Manager Peter Gelb’s subtle response was to try to censor the critics, barring one publication that receives Met money from reviewing any future shows after it printed a negative review, before facing a firestorm of protest and recanting. But you don’t get a sense of these follies in Wagner’s Dream, a gushing, insider’s look at the four operas that could have been produced by the Met’s PR department. Director Susan Froemke’s backstage access is something of a coup, but it comes with a price. We are told whatever disasters befall the Met are a testament to their grand ambition. In truth, they were so grand that it sunk the whole thing.