Every record was a shock when it came out. Compared to rabid R&B evangelists like the Rolling Stones, the Beatles arrived sounding like nothing else. They had already absorbed Buddy Holly, the Everly Brothers and Chuck Berry, but they were also writing their own songs. They made writing your own material expected, rather than exceptional. As musicians, the Beatles proved that rock & roll could embrace a limitless variety of harmonies, structures, and sounds; virtually every rock experiment has some precedent on Beatles records. As a unit the Beatles were a synergistic combination: Paul McCartney's melodic bass lines, Ringo Starr's slaphappy no-rolls drumming, George Harrison's rockabilly-style guitar leads, John Lennon's assertive rhythm guitar — and their four fervent voices. As personalities, they defined and incarnated Sixties style: smart, idealistic, playful, irreverent, eclectic. Their music, from the not-so-simple love songs they started with to their later perfectionistic studio extravaganzas, set new standards for both commercial and artistic success in pop.