This is truly the definitive book for anyone serious about training in Krav Maga. The books breaks the system into levels illustrating each technique and walks the reader through each step.
I am a professional Krav Maga Instructor (Krav Maga Bristol) and am fortunate that the Krav Maga syllabus is so well laid out for Instructors and students alike. Our students use it to prepare for lessons and gradings. Others use it to attend our bootcamps - in short if you are interested in Krav Maga this book is the place to start.
If you are going to buy any Krav Maga books I would suggest this is the place to start - there is about 4 years worth of material in it.
Finally, although the book is great - bear in mind it does not replace classes or instruction - its a guide thats all.