I have the hard-back edition of this book and it helped me get to grips with Aikido when I went back training in the art after a few years away from training. I had started training when in college but couldn't get my head around the mind-set of Aikido (i had trained previously in Karate) and as a result found it hard to 'stick with it'. When I found this book, everything clicked into place and I understood (better if not completely)the basic physical and mechanical principles of the techniques and also a whole lot more about the underlying philosphy of the art and of O'Sensei.
This helped me pick my next teacher well and his teaching style has me running to this book every so often to highlight key points and scribble in the margins. My only gripe is that some of the line drawings (very beautifully done) and diagrams are a little hard to follow, but having the technique applied to me/applying the technique to my training partner for real soon helped me to figure out which way was up.
DO NOT rely on this book to teach you Aikido. To learn Aikido (and any MA for that reason) you need a competent, qualified teacher who understands and has a passion for what they are teaching and aren't just going through the motions in a McDojo to pay the mortgage. DO rely on this book to supplement your experiences and learning in an Aikido. Works for me guv.