As a teenager during the heyday of "prog rock" in the seventies i had some pre-conceptions of what/who should be included in this book and my experience at the time revolved around the more prominent movers & shakers (love 'em or hate 'em!!) e.g ELP, Yes, Caravan, King Crimson, Camel & Jethro Tull. Having said that i also had a liking for lesser mortals Jade Warrior, PFM, Supersister & Greenslade.
I was a bit (pleasantly) surprised then, after purchasing this book, that it actually covers a much wider area of music, as eloquently explained in the introduction by Mr Snider. What you get is actually a guide to "progressive" (in the general sense of the word) music as opposed to just "prog rock" (as defined by the above bands).
The book is written by reviewing albums chronologically from 1967, opening with Sgt Pepper, to 1979, ending with Pink Floyd's "the wall". Most albums get a full page review , which are full of information & expertly written, and as well as the bands mentioned above (notably missing though is Supersister??) also includes such non-prog bands as Gong, BJH, Fairport Convention, Hatfield & the North, Hawkwind & The Moody Blues. Mr Snider has an obvious love of this music, which shines through in his writing and he also includes some band discographies and lists of essential albums.
A lot of the (British) music was very familiar to me but there was also numerous other European bands covered whom i'd never come across before, especially an amazing number of Italian & German artists, and for me that was the most interesting part of this book. If you're only interested in actual "prog rock" you might be disappointed in this one but if you love music that doesn't conform to the norm this is a great read.