In mid-May, a Federal Express package containing three copies of a 226-page musical manuscript thumped on the desk of Sarah Billinghurst, the assistant manager for artistic affairs at the Metropolitan Opera. It was sent by Tan Dun, the Chinese-born avant-garde composer whom the Met had commissioned eight years ago to write an opera. Seeing the half score, Ms. Billinghurst said she felt “ecstatically happy.” …

It will be, Mr. Tan promises, invoking his favorite word, “fantastic.”

One thing is certain: it will be unlike anything that has ever been seen or heard on the Metropolitan Opera stage – and will contain sounds that many have never before realized could be music. If this ambitious and experimental project succeeds, it could widen the possibilities of opera as a whole, expanding its entire future. It may also allow the Met, an august institution with an aging fan base, to expand its own future by reaching out to a significant new audience. And the process of the opera’s creation will shed light on the ideas and methods of one of the most uncommon composers at work today…