and Dean's "Dead Man's Curve", the Shangri-Las' "Leader of the Pack", and perhaps the subgenre's most popular, "Last Kiss" by J. Frank Wilson and the Cavaliers. In the early 1960s, Britain became a hotbed of rock 'n' roll activity during this time. In late 1963, the Beatles embarked on their first US tour and cult singer Dusty Springfield released her first solo single. A few months later, rock 'n' roll founding father Chuck Berry emerged from a -year prison stint and resumed recording and touring. The stage was set for the spectacular revival of rock music. In the UK, the Beatles played raucous rock 'n' roll – as well as doo wop, girl-group songs, show tunes – and wore leather jackets. Their manager Brian Epstein encouraged the group to wear suits. Beatlemania abruptly exploded after the group's appearance on The Ed Sullivan Show in 1964. Late in 1965, the Beatles released the album Rubber Soul which marked the beginning of their transition to a sophisticated power pop group with elaborate studio arrangements and production, and a year after that, they gave up touring entirely to focus only on albums. A host of imitators followed the Beatles in the so-called British Invasion, including groups like the Rolling Stones and the Kinks who would become legends in their own right. As the counterculture movement developed, artists began making new kinds of music influenced by the use of psychedelic drugs. Guitarist Jimi Hendrix emerged onto the scene in 1967 with a radically new approach to electric guitar that replaced Chuck Berry, previously seen as the gold standard of rock guitar. Rock artists began to take on serious themes and social commentary/protest instead of simplistic pop themes. A major development in popular music during the mid-1960s was the movement away from singles and towards albums. Previously, popular music was based around the 45 single (or even earlier, the 78 single) and albums such as they existed were little more than a hit single or two backed with filler tracks, instrumentals, and covers. The development of the AOR (album-oriented rock) format was complicated and involved several concurrent events such as Phil Spector's Wall of Sound, the introduction by Bob Dylan of "serious" lyrics to rock music, and the Beatles' new studio-based approach. In any case, after 1965 the vinyl LP had definitively taken over as the primary format for all popular music styles. Blues also