Pianos have souls, and if anyone doubts it, the documentary ‘Miracle in a Box’ should set the record straight. Covering the drama and aftermath of the First Berkeley Piano Competition, the film glides over the winner to turn the camera on the bequeathed prize: a 1927 Steinway grand piano in need of repair. Piece by piece and string by string, the piano is restored with delicacy, care and measurements down to the tenth of a gram. Anyone who’s given time and love to once-beautiful works of art, be it furniture, automobiles, bikes or instruments will find much in common with the craftsmen in the film, and John Lithgow’s narration helps Oscar-winning documentarian John Korty’s film drive home the triumph of restoration. Korty appears in person to screen the film on Thursday, Dec. 2, at the Bay Model Visitor Center. 2100 Bridgeway, Sausalito. 6pm. Free. 415.381.4123.