One of the most commercially successful rock/pop bands of the 1970s, the Doobies evolved from a roots-influenced, post-hippie West Coast rock outfit with dazzling guitar work into a pop-conscious, keyboard-dominated ensemble tinged with R&B and fronted by the distinctive, soulful vocals of Michael McDonald. Though they found their greatest chart success with McDonald, the band's early recordings with singer Tom Johnston produced some impressive hits as well ("Long Train Running," "Without Love," "Black Water")