I was just wondering which books work well as reference material with Google. I was looking at this book:

Pay-per-click Search Engine Marketing Handbook: Low Cost Strategies to Attracting New Customers Using Google, Yahoo & Other Search Engines (Paperback)
by Boris Mordkovich, Eugene Mordkovich


It seemed to get good reviews on Amazon. There are a few other books but they seem to be off base or not as helpful. I have been working with ad words for a few months now and just want to advance my skills further. Thanks everyone.