Cathleen Schine, a purveyor of sharp social comedies often sparked by touchy family dynamics, is a fly you don’t want on your wall during heated dinner-table discussions. Her 12th novel is abuzz with biting repartee. “Künstlers in Paradise” is a wise and witty multigenerational fairy tale about “glamorous exile” in Los Angeles, and like most fairy tales—even those with happy endings—it has dark undercurrents. Yet even the terrors and upheavals of the Holocaust and the Covid pandemic shared by the aptly named Künstlers—German for “artists” or “performers”—are lightened by Ms. Schine’s wry, breezy tone. The result is a moving and...