I had already read several other books on Google Adwords, but when I saw that this book was written by a "Google insider" I was intrigued enough to buy it. Unfortunately, at the time I bought it the book had just been published, so there weren't any reviews warning me to stay far, far away.
First of all, this book is very poorly written - poorly structured, very few screen shots, and confusing instructions. The author obviously is not a professional writer. However, I could overlook that issue if the author had some valuable Google Adwords insights, which he theoretically should have because he claims to have work at Google as an Adwords expert for about 4 years. But was there wasn't one piece of advice in the entire book that I would consider "insider" advice. Not one.
Most of the book consisted of vague general advice, or advice that anyone with half of a brain could figure out. Things like (and I'm paraphasing here) "If you have an ad running on Google, and it has been running for several weeks and has been shown thousands of times but very few people are clicking on your ad, then you might want to try deleting that ad and writing a different ad." Hmmmm, that's supposed to be "Google insider" advice? Sounds more like common sense to me.
And then at the end of the book, the author claims that he wasn't allowed to put the really good stuff in the book because it is, in his words, "too controversial", but if you go to his website and give him your email he will let you download the second half of the book that he wrote but that supposedly his publisher wouldn't allow him to put into the book. Give me a break.
In short, this book isn't easy enough to understand for a beginner, and has no advanced tips that would help an expert.
If you are just getting started with Google Adwords, here are the two best books. First, "Google Adwords for Dummies" by Howie Jacobson, is very good at going step-by-step showing you exactly how to set up a Google Adwords account. (I don't like most Dummies books, but this one is really good.) Second, "Ultimate Guide to Google Adwords - 2nd Edition" by Perry Marshall and Bryan Todd gives excellent advice on Google Adwords strategy, including many useful tips on testing and increasing conversion rates not included in the Dummies book. The two books approach Google Adwords from different angles, so I recommend that you buy both books.
But whatever you do, don't waste your money on "Google Adwords Insider" by Simon Leung.