This is the fourth in the series of phenomenally successful training manuals by the world's leading trainer and his star pupil. By instilling players with an understanding of persistent positional features, they stress the features of positional play most relevant to the practical struggle, assuring over-the-board success.
This book is definitely for an intermediate-advanced audience. Many statements of why a certain move is bad (for tactical reasons) leave it up to the reader to figure out why. It sometimes took me a minute or so to figure it out for myself. It is pretty good about explaining why certain moves are good or bad for positional reasons (after all, this is a book about positional play).
I got a little more insight into the principle of two weaknesses and prophylactic thinking, as well as a few specific tips. The rest of the material was not particularly helpful to me.
The exercises are very hard. Even the author’s expert students were only able to get half of them right!