I purchased this book a couple of weeks ago after hearing glowing reviews from a friend. I also checked out what amazon reviewers had to say before purchasing and was anticipating a valuable learning experience. I skimmed through the book, then decided to take the online survey. But when I entered the code, I was informed that it was no longer valid--had already been used. Now since I bought a new copy from Amazon, I can only assume that somewhere along the line another person knew what to look for and registered that code. Although I will still read the book and probably gain some insight, I was particularly interested in incorporating what I would have learned from the survey. I'm very dissatisfied for the first time in my long association with Amazon.