AndreasD reviewed Di Guoyong on Xingyiquan by Andrea Falk
This is the best book on the art in English that I know of
5 stars
If you are interested in the art of xingyiquan, this is the book you should seek out. The translator, Andrea Falk, now also sells the book in three paperback volumes, which I strongly recommend.
Di Laoshi covers the art from all angles in his book, with the five element fists, the animals and also weapon training and teaching methods and forms. It's the complete deal.
Naturally, you can not learn the full art from a book, but with this book you have a very solid foundation as a reference. It's a true treasure, and one of the martial arts books I most often consult.