As bassist in The Section, the L.A. session collective that was to the '70s what The Wrecking Crew were to the '60s, Leland Sklar helped define the '70s singer/songwriter sound. With agile, elegant, unfailingly supportive basslines, the man with the waist-length beard could pump fuel into Jackson Browne's engine on the rocking "Running on Empty" and fall like a gentle summer shower onto James Taylor's "You've Got a Friend" with equal expertise.