I purchased this book based solely on the reviews posted here. I immediately noticed some typos and more importantly, a couple of wrong answers in the chapter quizes. The wrong answers are what has really scared me - in one instance, the explanation for the answer they give contradicts the answer given. I stopped studying from the book so that I could obtain the errata sheet - I certainly didn't want to learn incorrect information/techniques. To my surprise, I didn't find any errata sheets on their website, so I e-mailed customer service to obtain one. I was given a one-page errata for the Practice Test only - these were errors I hadn't noticed, but they stopped at the Practice Test - they didn't proceed into the chapters of the book. When I asked Customer Service for a more complete errata, they responded that they didn't have one.I find it difficult to study from a book in which I have no confidence.