Over the Rainbow, Stormy Weather, and One for My Baby are just a few of Harold Arlen's well-loved compositions. Yet his name is hardly known--except to the musicians who venerate him. At a gathering of songwriters George Gershwin called him the best of us. Irving Berlin agreed. Paul McCartney sent him a fan letter and became his publisher. Bob Dylan wrote of his fascination with Arlen's bittersweet, lonely world. A cantor's son, Arlen believed his...