this book obviously is a milestone in martial art books. There is no such books for decades since the early 1900s. The other book from xingyi world is of course the complete works of Sun Lutang. Surely Sun is of higher grade, but this books is more readable and down to earth for the average practitioner.
It is also of great reference value for taichi and pakua learners if they got a broad mind.
If one practises some xy , it is very easy to read. If not then the reader would miss a lot of good points. My advise is, as xy is really so easy to learn[though not easy to perfect], why not learn a bit and then re-read this book. Surely it is very rewarding.
The book got excellent part on how to practice the sword and perspective on how to read the books of the 1900s. I read such books decades ago. But only after reading his book then I really understand what is written behind the words of the books and names he mentioned.
For the xy and neigia world , this book is really a landmark monument.