Cheng Man-Ch'ing is a cult figure in taiji, with a fiercely loyal group of followers. Certainly he was a master, and this book provides excellent photos of him doing the form. But taiji is all about movement and feeling, and still photos can't convey the quality of movement or hint at the internal mechanics of the art. So if you want to use the book to learn the form, forget it. If you have a good teacher, and want the book as a source of inspiration, by all means, buy it. If you're a Cheng Man-Ching fan, keep in mind that he talked and wrote about taiji, but much of his power was derived from nei gong, including the small and great heavenly circulations, that he kept a closely held secret, for reasons that remain unclear. Temper what he says with the understanding that he held back as much as he offered, and you won't be frustrated by doing the form over and over without getting anywhere near the benefits Cheng derived. Bottom line is that the book is an artifact and a good one, and it was one of the first books in English on taiji. As a learning tool, it is limited.
This might have been the first work in English on tai chi, and Smith was Cheng Man Ching's first western or American student. It's still one of the best introductory tai chi books out there. The photos of Cheng's form are worth the price of the book by themselves, his form being impeccable as usual and a high benchmark we should all strive to attain.
One caution, which is that the photos of Cheng are from two other previous books and some are reversed from what they are in the actual form; for example, single whip is shown on the left side when it is actually done on the right side. You can tell they're from different books since some photos show Cheng in a white jacket, and others show him in a dark jacket.
Smith includes the best brief, several-page summary of tai chi history and its origins I've seen, giving you essential details and facts without getting into an overly meticulous recounting of its origins, the lineage, and other controversial issues, which are still unresolved, anyway. But if you become more of an advanced student you'll want to learn all about that later. For an introductory text this is enough information for now.
A nice chapter on the martial arts applications is also included, something neglected too often in present day tai chi texts. Also, some good information and instruction on pushing hands techniques. By the way, pushing hands was a skill added to tai chi much later, it being originally a dim mak or point striking art, which most practitioners aren't aware of.
One minor quip. The pictures for the photo sequences of Cheng's form are a little small and sometimes a bit dark by present reproduction standards, but one has to remember these plates are now almost 40 years old. However, they're still good enough so you can see the postures and techniques okay. Overall still a fine book and at this point a true classic and landmark in the history of martial arts books about the more obscure Chinese arts. Smith's books on hsing i and ba gua were also important early efforts and excellent books also, and if you are interested in further information on the two other Wu Dang internal arts those are working getting too.