In 1979 a onetime R&B singer whose small New Jersey record label was about to implode listened to a DJ rap at a Harlem nightclub. It was the first time she'd ever heard anything like it. "A spirit said to me, Put a concept like that on a record and it will be the biggest thing you ever had," said Sylvia Robinson 25 years later. She assembled a trio, laid their rhymes over a beat and helped make "Rapper's Delight" the first hip-hop smash. Robinson, who died Sept. 29 at 75, also produced "The Message," hip-hop's first socially conscious song. Her label, Sugarhill Records, collapsed, but Robinson was known as the Mother of Hip-Hop for helping spread the genre around the world.