This is incredibly detailed and practical guide to the principles and practice of the 89 Posture Wu Style Tai Chi.
Written by the daughter and son-in-law (who were both students of the founder of the Wu Style), this text speaks with authority based on a lifetime of experience(60+ years of practicing and teaching for both) and original family documents outlining the correct naming, execution and principles of this style.
The authors use quotations from the classics sparingly but provide copious detail on what these principles mean, how they're experienced and how they're applied.
Included are common errors students make and guidelines for correcting/avoiding, based on the authors' own personal experience and expertise.
The detailed explanations of mental and bodily preparation as well as managing the chi should be of particular use to new practitioners (like myself) or those with limited access to a qualified instructor.
The detailed explanations of the postures and transitions, along with the line drawings and photos should be helpful for all in evaluating the accuracy of their movements and their alignment with the principles of Tai Chi.
While I cannot imagine learning from this book alone (based on my own limitations, not the authors), it's quickly becoming invaluable in my daily study and practice.