This book was published in 1984, so a lot of water has gone under the bridge since then, but this remains an excellent account of Black Sabbath up until that point, dealing with their startup, massive success, break up with Ozzy, Ronnie James Dio and Ian Gillan eras. Having also read Ozzy's autobiography, it's interesting that there is general agreement. I liked the part where Ozzy painted himself purple to get a rise from the crowd in Hamburg, and achieved nothing, and when they defused a devil worshippers' meeting backstage by singing childrens' songs. Top reading for all metal fans.