Rap pioneers the Sugarhill Gang (left to right: Wonder Mike, Master G and Big Bank Hank) perform live circa 1979. Michael Ochs Archives/Getty Images hide caption

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Carole King, composing. Evening Standard/Getty Images hide caption

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Al Green, from the cover of his Greatest Hits album, first released in 1975. Courtesy of the artist hide caption

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Paul Williams, Eddie Kendricks, and David Ruffin of the Temptations, in 1965. Hulton Archive/Getty Images hide caption

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Mama Cass Elliot with her Mamas and the Papas bandmates John Phillips and Denny Doherty in 1966. Express/Getty Images hide caption

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Composer Richard Rodgers in London for the opening of 'The Boys From Syracuse'. Ted West/Getty Images hide caption

itoggle caption Ted West/Getty Images