As their sixth international studio release, Back in Black was an unprecedented success. It has sold an estimated 50 million copies worldwide. It is one of the best-selling albums in music history. The band supported the album with a yearlong world tour, cementing them among the most popular music acts of the early 1980s. The album also received positive critical reception during its initial release, and it has since been included on numerous lists of "greatest" albums. Since its original release, the album has been reissued and remastered multiple times, most recently for digital distribution.