As part of my CELTA course, this book was recommended.
This is a useful reference book to learn the background to language teaching, some key concepts and explores ideas of language teaching. It doesn't recommend as much as mention what methods are used. It is a quite an objective and informative book and does cover a comprehensive set of topic areas in teaching.
I have found that a lot of the teaching training classes have lessons taken out from this book so definitely worth it for the course! However, it is a little hard to read and you are often trying to read between the lines. I do often find myself asking questions after reading it so things are not as clear as they could be as to which method is generally considered 'better'. This is can be a good thing as it invites the reader to make their own judgements. The author of the book actually teaches at the school I am being trained at. He is a well respected ESL expert and active in the practice.
Though in just my opinion, a lot of what he says could be cut down to a mere few sentences. The book is very long and heavy to carry around. If I were to re-write I would cut out a lot of the author's commentary and side/background information which isn't particularly useful and place them in an appendix (perhaps as a separate booklet) as when you're looking for specific information, there's an awful lot of scanning involved.
I favour Learning Teaching by Jim Scrivener which is written much simpler, easy to follow and is more 'modern'. Plus you can go in and out of the book fairly easily.