One recent Friday evening, in a darkened, wood-paneled Baltimore concert hall, audience members rose up in their seats, yelling, clapping, and singing--in the middle of a classical music performance. To be fair, this wasn't exactly "classical music." It sounded like Rachmaninoff and sometimes Bach, but the pianist, Gabriela Montero, wasn't playing from a book or memory; she was creating music on the spot.

Improvisation has historically been considered heresy by the classical music establishment. This TNRtv report profiles the musicians who are driving a highly controversial movement to change that. Will they trivialize the classical genre? Or save it?

Ben Eisler is a video reporter-producer at The New Republic