Master of Reality

Master of Reality is Black Sabbath's third studio album, recorded at Island Studios in London between February and April 1971. It followed their first two records of 1970, and it was the last one produced by Rodger Bain. Tony Iommi took over production duties from the next album onwards. Released in the summer of 1971 on Vertigo Records, it reached number five in the UK and number eight on the US Billboard 200.

The record is worth hearing for how low and heavy it sounds. Iommi and Geezer Butler downtuned their instruments, which Iommi said gave a "bigger, heavier sound", and with more time to write and record, the band took a more experimental approach. Critics were unkind on release, but the album is now rated among the great heavy metal records, and some see it as a root of stoner rock and sludge metal. It has sold over two million copies in the US.