This book contains a wealth of detailed information and reflects a great deal of research but it also promotes the short but expensive (and completely unnecessary) "TEFL" certificate courses sold on the web. Such courses claim to "qualify" you to teach English as a foreign language and are frequently promoted through false advertising on the web: "You'll need this to get a job," and even bogus want-ads: "Teacher wanted - TEFL required" from non-existent schools.
The author is a Canadian who taught in Britain so her personal experience in teaching abroad is rather limited, but I would imagine that after so many editions she should be fully aware of the TEFL fraud and refuse to promote it. Books like "Teach English in Italy," although more narrow in scope, document that most genuine employers don't even request, let alone require, any short certificates, and may even laugh at an applicant's TEFL "qualification."
I would have preferred to read a book describing the author's personal experience as a foreigner teaching in Britain, since that's what she knows best, and many Americans would love to teach in the UK.