In the 1970s, when popular music on both sides of the Atlantic fragmented into disco, soul, hard rock, pop, and folk, Elton John embraced them all with his signature creative panache. Emerging in the late 1960s as a singer/songwriter, Elton was widely acknowledged as the most prolific pop and rock star of the decade by the mid-1970s. His peerless musical style and ability to jump from sensitive ballads to bawdy rock anthems to campy pop have made...