Gérard Caussé is among the few classical violists who maintains an international solo career, and, with Nobuko Imai, is one of the two most significant stars of the instrument since William Primrose. He plays a very old (1560) viola by Gasparo da Salo. Caussé is closely associated with the chamber music of Mozart, who, he says, was the first composer to realize the viola's potential as the "mediator" between the upper and lower voices of the orchestra and the string quartet. He also plays the music of the two Romantic-era composers who most prominently favored the viola, Hecto...