The concept album, initially defined as an LP (long-playing record) recording wherein the songs were unified by a dramatic idea instead of being disparate entities with no common theme, became a form of expression in popular music in the mid-1960s, thanks to The Beatles. Their 1967 release of Sergeant Pepper's Lonely Hearts Club Band is generally recognized as the first concept album, although ex-Beatle Paul McCartney has cited Freak Out!, an album released in 1966 by Frank Zappa and the Mothers of Invention, as a major influence on the conceptual nature of Sergeant Pepper. During the rest of the decade, the concept album remained the province of British artists. The Rolling Stones made an attempt—half-hearted, according to many critics—at aping the Beatles' artistic achievement with Their Satanic Majesties Request (1967). Other British rock bands, notably The Kinks and The Who, were able to bring new insights...