The Battle for Black Sabbath
by Garry Sharpe-Young
Setting aside the atrocious cover, this book is incredible. So many intricacies of Black Sabbath explored and unveiled with tons of great stuff on Ozzy, Dio, Tony and all phases of the band's evolution or devolution, mob ties, discarded members, etc.
Just over 300 pages of text dense pages.
A decent amount of pictures, too, and not just generic ones plucked from the internet.