I passed both exams using only this book! My two tests included 81+94 questions and this book has answers on all of them except probably one or two. Sun exams have low passing score ( 70-75% ) and I think it's possible to answer about 80% using only this book for preparation. But if you want to answer >90% it could be very difficult task because some questions are very tricky (like command flags, CDE filenames) and you have to have extremely strong real work background to answer them.Moral is simple. If you want just pass exams - this book is right for you!