It's one of the great debates in musicology and the answer is as complicated as it is hotly contested. Popoff's Who Invented Heavy Metal? provides the most detailed, well argued, reasonable, ridiculously complete, and most lively and readable telling of the early history of heavy metal yet, arming the argumentative headbanger with all the facts and figures one needs on hand to win those bar room bets around this provocative question.
Ultimately, Who Invented Heavy Metal? aims to be a book that doesn't limit itself to heavy metal fans. The book provides wide instructional scope of teachable moments through unfolding, subconscious, telling by osmosis of the very history of heavy metal's origins through events inside the genre but, surprisingly, many events outside of its own kerranging reverberations.
Divided into four parts: Trace Elements: 1250 BC - 1966, beginning with the Battle Of Jericho through shocking concerts in ancient Greece, Vikings, Paganini, the blues, the invention of the electric guitar and why Little Richard, Elvis, Eddie Cochran, Jerry Lee Lewis - but most notably, Johnny Burnette, might be called the first headbangers. Lead: 1967 - 1969: Discussing extreme vocals, distortion, feedback, guitar heroes, psychedelics, amplification, the first riffs, the first power chords and the first heavy metal songs.
Steel: 1970: where Martin argues for the "real" or "correct" answer to the titular question being Black Sabbath given their groundbreaking Black Sabbath album, but also that band's Paranoid, Uriah Heep's debut, and most important of this set of three, Deep Purple's In Rock. Dozens of other bands are discussed as well.
Titanium: 1971: In the final stretch Popoff talks about the wildest, heaviest full albums of 1971. Readers should come away with a new way to look at this question, whether they become convinced of Martin's arguments completely or not!