The book gets off to a dodgy start - Magma a German band; 'Revolver' a 1965 album - but the authors eventual settle down into quite a nice groove. The writing is not for the casual reader - a bit of effort is required. The early sections cover ground that will be quite familiar to readers of other prog. books - perhaps too familiar - and the interpretations of lyrics and concepts are, at times, specious, though this is common enough in books on the genre. It's the later sections that I found most interesting - on women in prog., on progressive metal (even though I don't like the stuff), and on progressive folk. The chapter on jazz-rock fusion, by contrast, is quite poor - though I'm an aficionado and clearly the authors aren't. All-in-all, a worthwhile addition to the growing canon of prog. tomes. Not for me as snappy as Paul Stump's frequently derided 'The Music's All That Matters' but an enjoyable read just the same. Prog. fans can be very confident that the authors are taking their music seriously - which is as it should be.