In the late 1970s, there was an artificial divide in the pop-music scene. “Disco sucks!” chanted some white rock & rollers who were threatened by the ubiquitous popularity of such black forms of music as funk and disco. Such provincialism seems quaint today, but back then a few guitar-based bands were so threatened by advances in technology that they proudly declared their recordings were synthesizer-free. None of that mattered to guitarist Nile Rodgers, who drew from the same blues and R&B influences as rockers but blended them with sleekly danceable rhythms on such hits as “Everybody Dance” and “Le Freak,” which were distinguished by his insanely tight and slinky riffs. By the early ’80s, Rodgers’ skills as a producer and sideman were openly prized by both rockers (David Bowie, Power Station) and pop stars (Madonna).