The Question of Instrument: Part I of the series "Glenn Gould Plays Bach" is devoted to Bach's "Art of Fugue." Gould's performance is followed by a lively repartee with Monsaingeon, in which the pianist provides dazzling insights illustrated by music examples. He explains, for example, why he plays some pieces extremely slowly, and bemoans the "musicological overkill" of scholars who insist that Bach's keyboard music should only be played on a harpsichord.