I wouldn't call a single man a good source of looking at a whole country's Buddhism, not to mention that TNH is a very creative and innovative teacher (this is not criticism).
Of course, I reflected on this later and thought about how silly the question may have been. I have always had the assumption that Thien could be considered a different school of Zen almost. When I saw your description of the book, I was thinking it would be along the lines of Shunryu Suzuki writing a commentary about the teachings of Lin Chi or something- a sort of cross-schools study. I suppose it may not be so. I will just have to pick it up for myself.
To get back on topic, I have read a lot of TNH's books. I would say that if you are already interested in his teachings, you probably won't go wrong with picking up almost any book. Obviously, you might not get what you are looking for if you get Chanting from the Heart
, Touching the Earth
, or any of the other books that are not really collections of teachings or explanations per se, are more oriented towards the actual "rituals" of practice. Those are still interesting, if you have time to explore.
Thich Nhat Hanh has a commentary on the Heart Sutra that is easy to read, so if you know anything about that particular Sutra, you can probably get a good idea concerning his teaching by comparison.
Like I said, I have read a lot of his books. However, the one I had trouble with was The Sun My Heart
. It took me a little longer to get into it. There are a few chapters at least that talk about some rather tough (for me) physics theory. I loaned it to a friend who was a physics major in College and he never got around to reading it. Eventually I read it and liked it.
I hope this is clear.