This year, I have acquired a couple of books that I can recommend. One is an instructional manual by Chen Zhenglei for Laojia Yilu and Erlu. I’ve been using it as a review of Laojia Yilu, in connection with a video project comparing the Yang and Chen traditional long forms.
In this book, every movement of the form is described in careful detail, with multiple photographic demonstrations by the author (a grandmaster of such eminence that I don’t need to cite his credentials). You certainly could not learn this rather difficult routine by studying Chen’s book. But if you already know Laojia, it is an invaluable resource for refining and correcting your form. I am working it to tatters.
Another book that has recently come to my attention is Martin Mellish’s A Tai Chi Imagery Workbook: Spirit, Intent, and Motion. This beautifully illustrated volume uses sketches, photographs, and diagrams to evoke, explain, and describe the internal experience of Tai Chi.
This book is not a manual for learning specific forms or styles. Rather, it is a guide to fundamentals such as posture, stepping, balance, and breathing. It would be equally useful to beginners, more advanced students, and (especially!) instructors. It is an attractive and readable book, too.