It's not a bad book, but I have a few objections:
First, there's too many sentences like "I did this, a friend of mine did that, I was told..." and so on. I expected more facts, and less biographical moments.
Second, threre's too much emphasis on bamboo species I could hardly call temperate, like Drapanostachyum, Himalayacalamus, Chusquea. Theese species are suitable for subtropical or Mediterranean garden rather then for a temperate one.
Third, I can't remember ever reading in a gardening book things like "It's a second rate plant" The writer proclaimed the whole genus of Pleioblastus, and some others species as unwanted in a garden. I think that it's much better to illustrate the plants better, and leave up to a gardener to decide which plants he (or she) likes and which he does't like.