This book covers the koryu dai san kata from the Tomiki aikido system and not much else. For someone learing that kata it would be useful although you might as well get Dr. Lee Ah Loi's book and you get all the Tomiki Kata. In its favour this book is clearer than Dr. Lee's with a number of photographs for each technique. A limited book done well enough.
Any keen practitioner should know not to limit them selves to one thing and to broaden their horizons must research various material, on their chosen subject this book is good for reference and deserves a place on the book shelf of any Aikidoka.