Thea Musgrave is 98, and by her own account she is still learning. Her 1977 opera "Mary, Queen of Scots" is opening at the San Francisco Opera, returning one of the Scottish-born composer's defining works to a major American stage.

Musgrave composed "Mary, Queen of Scots" in 1977. The opera stands at the center of a long career that, as she describes it, has been devoted to searching for what she calls the "dramatic abstract" — a way of writing music that carries theatrical force without surrendering its abstract, symphonic integrity.

That search has never ended. The composer's own framing of her career is not as a finished achievement but as an ongoing process of discovery. At 98, she says she is still learning — a statement that reframes the San Francisco revival less as a retrospective tribute than as a checkpoint in a continuing project.

The San Francisco Opera's decision to stage "Mary, Queen of Scots" gives audiences a chance to hear the work of a composer who has spent decades insisting that opera can be at once rigorously constructed and theatrically alive. The opera itself, built around the doomed Scottish queen, has long been recognized as a landmark of Musgrave's stage output.

What the revival underscores is the durability of Musgrave's central question. The "dramatic abstract" — her term for music that behaves with dramatic logic while remaining absolute music — remained her pursuit across a career that now spans well over half a century. That she still frames her work in terms of learning, rather than mastery, is the sharpest fact of all.

As the production opens in San Francisco, it extends that pursuit to a new audience, and to a composer who has not stopped asking what music for the stage can do.