He has a simple and compelling thesis, that change in musical tastes and styles almost always comes from marginalised and excluded groups in society; foreigners or lower classes, almost never the elite. Transgressive music promoting violence, sex, drugs and altered conciousness is almost always more compelling than turgid elite sponsored themes glorifying rulers or nations. The book is a historical romp from ancient times through to the present showing one wave of musical revolution after another. Each revolution eventually gets absorbed and tamed by the mainstream. He gives the example of “classic rock” as a case study of a music that once seemed so threatening, but is now deemed mainstream cannon. It was a fascinating thought provoking read. It’s changed the way I think about music history. But perhaps it was a little long winded in places.