A heavy, heavy, heavy album; it feels like a great, powerful weight as it bombasts along and Ozzy's vocals are excellent alongside dirty guitars and an insistent, urgent rhythm section. Unlike future iterations of the genre, the production enhances rather than overpowers the songs whilst maintaining a mood. The ballad Changes is a gear shift - one of a few moments on the record for the listener to breath - and is surprisingly emotional and moving. Indeed, a lot surprises to the casual listener, including how tuneful and well constructed the tracks are. Black Sabbath have been a real surprise to me on this listening journey and this is an impressive album to add to the list of records I will revisit.