Back Stabbers -- that minor-key piano riff, those strings, Eddie Levert's warning about the friends who smile in your face -- made paranoia funky. Love Train made unity irresistible. For the Love of Money has a bassline so iconic that hip-hop has been mining it since the first beat was laid down. Ship Ahoy tackled the Middle Passage with strings and drama and a conviction that soul music could be political and beautiful at the same time.

They're still performing. Still dressing sharp. Still singing those songs with the same conviction they had in 1972. The O'Jays weren't just a vocal group. They were the voice of Philadelphia International Records -- the label that proved Black music could be commercially dominant without compromising its artistic ambition. Love Train is still rolling.

The O'Jays -- Love Train. Back Stabbers. For the Love of Money. Philly soul at its most urgent. The bassline's still being sampled.