Revolver (Beatles album) as the Beatles'. While also highlighting the importance of the production, David Howard writes that "Revolver" was a "genre-transforming album", on which Martin and the Beatles had "obliterated recording studio conventions". Combined with the similarly "visionary" work of American producer Phil Spector, Howard continues, through "Revolver", the recording studio had become "its own instrument; record production had been elevated into art." Whereas "Sgt. Pepper" had long been identified as the Beatles' greatest album, since the 2000s "Revolver" has often surpassed it in lists of the group's best work. Sheffield cites the album's 1987 CD release, with the full complement of
1 (Beatles album) of America. The album is the best-selling album of the 21st century in the US and the fourth best-selling album in the Soundscan era (1991–present). As of February 2014, the album has had sold 12,410,000 copies in the US. In the US, the album secured the Beatles a fourth decade in which they placed an album at number 1 on the "Billboard" chart. In Canada, "1" debuted at number 1 on the Canadian Albums Chart, selling 54,668 copies in its first week. The album was certified Diamond (1,000,000 units) by the CRIA in February 2001, just four months after its