John Adams previews his new opera about the atomic bomb. “Adams’s third opera, which has been in the making for five years, is his first return to the medium 14 years after achieving worldwide notoriety with two provocative and now seminal works, Nixon in China and The Death of Klinghoffer. According to Ms. Rosenberg, it took a bit of persuading to lure Adams, whom she described as ‘the greatest composer alive today,’ back to the world of opera. But ultimately the saga of the bomb’s conflicted inventor J. Robert Oppenheimer, which Rosenberg proposed to Adams, proved too operatic to turn down. Sellars described recently declassified government documents, incorporated into the libretto, which might fundamentally change everyone’s perception of this world-changing event.”