DAVID LANG first heard Wagner’s “Tristan und Isolde” at the San Francisco Opera in 1974, as an undergraduate student and aspiring composer. This was the first opera ticket — standing room — that he had paid for with his own money, and he arrived well prepared, with a copy of the score and a flashlight to study it by.

“It was a really big deal for me,” Mr. Lang, now 55, said recently, sitting on a sofa in his light-flooded SoHo loft while two parakeets called noisily for attention from another room…

David Lang’s prisoner of the state—co-commissioned by the New York Philharmonic, De Doelen, Barbican Centre, L’Auditori, Bochumer Symphoniker, Concertgebouw Bruges and Malmö Opera – premiered in June 2019 with the New York Philharmonic, conducted by Jaap van Zweden, and received its British premiere in January 2020 at the Barbican Centre in London with BBC Symphony Orchestra, BBC Singers and conductor Ilan Volkov…