Opening with the age-old question of what was the first heavy metal song before launching into a metal head's history of the genre this fascinating documentary is a must. With interviews from rock greats like Lemmy, Tomy Iommi, Alice Cooper and Vince Neil to name but a few and concert footage of various heavy bands from Black Sabbath to Slipknot this is a sweaty, mosh pit inducing, bleeding ears look at what heavy metal music is and means to thousands of fans the world over. It is well made, surprisingly funny and brilliantly paced. There were moments in the film when the hairs on my neck stood up as memories were evoked by what I was watching. Seeing Rage Against the Machine performing killing in the name of and all the fans singing along reminded me of when I saw them fourteen years ago in room with no more than a hundred people. You can't beat the feeling of seeing a massive rock concert and the film manages to capture that feeling with the sights and sounds it is almost like you can smell the sweat. The makers also don't shy away from the controversy that has been levelled at the music over the years and delves into the various court cases and why so many believe it's the devils music. Overall it is a thoroughly engaging look at heavy metal and all that encompasses, made by a fan for fans but open to anyone, are you ready to rock?