I own and love this book. It is a super comprehensive guide to surviving all sorts of extreme emergencies in a variety of geographic zones and climates. Plane crashes, car crashes, getting lost in the wilderness, tsunamis, earthquakes, terrorist attacks - you name it, book covers it!
The author is an authority on survival, being the former survival instructor or the British SAS special forces troops, which operate around the world, from arctic to desert zones, and from big cities to remote jungles. Tone is very down-to-earth, and straight to the point. The book is easy to read and understand and does not assume or need any prior knowledge of military and survival techniques (which is the author's background). I am a former search-and-rescue team member and trained wilderness first-aid responder, and I find the information in this book first rate.
The content is very densely concentrated, so reading it once will not make you an expert. To make the best of this book, you need to practice some of the survival techniques. The best way is probably to go camping and backpacking, but you can try a lot of them in your own backyard.
The book overemphasizes outdoors survival (what plants to eat, how to fish and catch animals), which is due to the author's background as a special forces soldier. For more on urban disaster preparedness, read Cody Lundin's book "When All Hell Breaks Loose". Unlike Cody Lundin and many American survival books, the SAS Guide is refreshingly free of political statements and sticks strictly to the topic of survival :) The SAS Guide is about surviving a relatively localized and temporary emergency (measured in days, not years), and assumes you will eventually be helped, rescued or return to civilization. If you are interested in long-term survival of a total global catastrophe (aka "survivalism"), this is not the best guide.
It is such a great book that I am planning to buy more copies, to keep in my car, take when traveling, and give to friends. Highly recommended!