I really like this book. It is not so much an instructional book as a graded workbook. I would say it is half way between an instructional work and a test book. You are introduced to some concept, shown some examples, and then offered exercises to do (with a rudimentary scoring system). No effort is really made to teach you though - it's as if this were designed as material for coaches which I believe it is.
Jeremy Silman was disappointed that it was so dry (he's right) but this doesn't bother me at all. There are numerous books providing good instructive material on this or that topic but precious few that offer any kind of substantial course or progressive introduction of material. I guess this is what you pay a trainer for. This first volume looks like it could be the start of one and that would be a good thing. Actually Silman's own endgame book is very deliberately written to offer a progression of material and it is great (less dry too, for those who care).
The material is not difficult, but not beginner stuff (the Introduction suggests under 1500 ELO). The exercises at the end vary in difficulty so some are trivial and others require more effort. Also, the 24 chapters are brief and self-contained so you can stop and start frequently without losing focus.
My purpose in buying this book was to discover fundamental weaknesses that I had skipped over so I could fill in the blanks (the Introduction states that it will help "close any possible gaps in [the reader's] chess knowledge"). It is proving useful for exactly that purpose and it's finding plenty. You can be going along fine, your confidence growing, and then wham - a total blind spot. For me, the first was centralization where I was beyond bad - totally hopeless. It's exactly this kind of discontinuity in your knowledge that this book will discover for you, and fixing your weakest links just has to improve your results.
In essence I am paying for the author's proven skill in selection of material and recognizing what is relevant for a particular playing level. This is money well spent. Five stars if it had just a little more instructive prose.