The period when rock music became most closely aligned with art began in 1966 and continued until the mid 1970s. Academic Michael Johnson associates "the first documented moments of ascension in rock music" to the Beach Boys' "Pet Sounds" and the Beatles' "Sgt. Pepper's Lonely Hearts Club Band" (1967). Released in May 1966, "Pet Sounds" came from Wilson's desire to make a "complete statement", as he believed the Beatles had previously done with "Rubber Soul". In 1978, biographer David Leaf wrote that the album heralded art rock, while according to "The New York Observer", ""Pet Sounds" proved that a pop group could make an album-length piece comparable with the greatest long-form works of Bernstein, Copland, Ives, and Rodgers and Hammerstein." "Pet Sounds" is also noted as the first rock concept album. In 1971, "Cue" magazine described the Beach Boys as having been "among the vanguard" with regard to art rock, among many other aspects relating to the counterculture, over the period up to late 1967.