This exhilarating and inventive twin portrait of Beach Boys leader Brian Wilson does two things more conventional biopics about musicians do not: it illustrates the process of creation and provides real suspense. It focuses on two periods in the man’s life.

The first is in the ’60s, where he is played, brilliantly, by Paul Dano. He resigns from touring and, while the rest of the Boys are off in Japan, masterminds Pet Sounds, considered today to be one of rock ‘n’ roll’s greatest albums. We are taken through the process by which he built up “God Only Knows” and “Good Vibrations.” Fascinating. But he is at the same time beginning to lose his grip on reality.

The film toggles between this period and the ’80s, when Wilson is under the thrall of the manipulative psychiatrist Eugene Landy (an effective if slightly hammy Paul Giamatti), who overmedicates and abuses him. Casting John Cusack as Wilson for this period at first seems jarring, but the disconnect somehow works in retrospect. Also a terrific Elizabeth Banks as the Cadillac saleswoman (and future wife) who helped steer Wilson back to normalcy.

Needless to say, excellent sound design. BB fan or not, this is a must-see. Japanese title: Love & Mercy: Owaranai Melody. (120 min)