Harbison's work, titled Darkbloom: Overture for an Imagined Opera, was assembled by the composer from material written for a never-completed opera about Vivian Darkbloom, a secondary character in Vladimir Nabokov's Lolita.

"I have no regrets about relinquishing the project," Harbison writes in his program notes. "I no longer have any interested in composing unproduceable operas. Nor do I have any difficulty in understanding why certain material, even in the realm of opera (which has harbored fratricide, patricide, incest, and rape), in untenable on our stages regardless of its artistic merit."

"Though I regard my earlier engagement with the material as misguided, nevertheless I am reluctant as any artist to part with good material, and I am grateful for the Boston Symphony's invitation to write a short piece for its 2005-2006 season," he adds.

The program, which also includes Stravinsky's Movements for Piano and Orchestra and Brahms' Symphony No. 2, is repeated tomorrow afternoon and on the evening of March 26. Music director James Levine conducts.