During his tenure at Motown records, vocalist and songwriter Marvin Gaye expanded the boundaries of what soul music could address and how it could sound. His early Motown hits "How Sweet It Is (To Be Loved by You)," "Ain't That Peculiar," and "Ain't Nothing Like the Real Thing" (with Tammi Terrell) helped define the 1960s Motown sound. His 1968 "I Heard It through the Grapevine" became Motown's biggest-selling record to date. On genre-defying albums such as 1971's What's Going On, Gaye opened soul music to allow for overt political protest, while on 1978's Here, My Dear he reduced his subject matter to a level of pain and honesty that had rarely been touched in any form of popular music. During his lifetime, Gaye battled many demons—the most significant of which was his father, a man with whom Gaye had an ongoing, troubled relationship. That...