As a university student faced with the compulsory 'year abroad' teaching Engish for the British Council in an Italian high school - yet not actually having any formal teaching training - I found 'Learning Teaching' to be one of the best additions to my rapidly expanding collection of teacher training books.
It is approachable enough for somebody new to the field like me, whilst still maintaining an element of depth and not just being an overly superficial text. Each area is covered thoroughly and supported with practical examples, including some good lesson plans. I would recommend this book to training, new and not so new ESL teachers.
I would also recommend Jeremy Harmer, 'The Practice of English Language Teaching' as a good compliment to Scrivener's book.