This is a good and informative book that is amusing to read. It is hard to add anything to what has already been written in these reviews but here comes my little contribution. There is a wealth of information in this book, although, as other stated, biased towards dobsonians. My favourite parts are the good description of modern type of oculars and on urban observing skills. I think that Sidgwick's "Amateur Astronomer's Handbook" contains much more substance than this book, but as it is badly dated, I find the combination of both a very complete set of information for the amateur astronomer.
My only negative comment on this book is on the opening sentence in hack 27 ("Maintain an observing notebook"): "Being organized makes your observing sessions more productive". Of course the importance of a logbook cannot be overestimated in science (I am a scientist and know what I am talking about) and it is also central for the serious amateur astronomer. However, I was struck by the mentioning of the concept "productivity", as it seems to me extraneous and disquieting in the context of a hobby. Beware that this is my personal opinion, I really do not want to care about "productivity" in my hobby. As an amateur astronomer I observe the skies for the only sake of enjoyment and the feeling of awe about nature (although I do have an sketch- and logbook!).