The daughter of romantic idol John Gilbert offers a sympathetic, largely candid biography--which blames his downfall on a conspiracy of sabotage masterminded by MGM's Louis B. Mayer. Fountain sketches in Gilbert's early years; his storybook climb from teenage poverty to beginnings, as a gawky extra, in the silents; his rocky marriage to Fountain's mother, actress Leatrice Joy, who was the bigger draw at the start. Then comes Gilbert's mid-1920s burst...