My favorite Go book. It makes a promise and it keeps it. I have read it many times. First to approach shodan, then to reach it. Then to solidify the rank. Any 2 kyu reading this book will become a shodan. If you are weaker then wait. Read other books first.
Even after many years I think that it still delivers on what it is promising, even though some ideas inside it seem to have moved to the jyu level. A real eye-opener in most of its pages though, but be aware that it is not a book that will make you manage that breakthrough JUST by reading it. You will need to get out your stones and board and STUDY! Play out each and every diagram, feel the flow of the stones on the board, actually THINK each move as you place it on the board, even the ones the author considers trivial.
Solid ideas, great insight and a multitude of things to think about and improve.
The first study-through made me stronger than my 4-6kyu and now I am giving a run for their money to 1-2dan players in DGS. I have yet to win against them yet (mostly due to my horrible life and death problem skills - which is not the point of this book at all), but I have yet to resign in 50 moves, like I was forced to do before.
I plan on studying it many times more in the future. A masterpiece for teaching Go to us amateurs and a handbook that can actually get you to 1 dan eventually, by seriously studying it. What more can we ask .?.