In my opinion, you'd better read the whole book, it don't waste too much time. I've just finished the book within three weeks, even English is not my native language. I am using testpass exam for practice, which guarantees 100% pass. If you just want to pass a exam, but not learn a real things, you don't need to read the book. Just memories whole questions and answer of the exam. But if you want to get career of web app development, you'd better to learn step by step. Thanks. Good luck!