Would give this 4 or even 5 stars, but there are detractors that need to be brought to the consumer's attention.
I used this book along with the official Passing Your ITIL Foundation Exam text and an on-line Skillsoft class offered by my company to prepare for the exam. Haven't taken exam yet, but I feel very confident.
Only disappointments with this book is that, first, it explains only the right answers, not why the other answers are incorrect (the official ITIL book's chapter and overall exam prep does this however). The second disappointment is that this text strays from the official ITIL Foundation syllabus to bring in more detail about items that, while they may be on later, more advanced ITIL exams, they are not in the Foundation exam (at least, not supposed to be!). The 6th of 13 full practice exams was particularly bad in bringing forward non-foundation syllabus information--not exactly a confidence builder in preparing for the exam. It had me chasing my tail finding out other information that was neither in the Foundation text, nor in the Foundation syllabus.
Might be good for exam prep, but be aware that it will test non-Foundation level ITIL material. Best of luck!