Darrell's book is far more helpful than the manual. It's laid out in a much more logical, easier to navigate order than the Nikon manual. It not only tells you what the different buttons and settings on your camera do, but WHEN and WHY you might want to use them (or not use them)-- that is a huge difference between the book and the manual. The book has a section at the end of each chapter called "Recommended Settings" that I believe most folks will find very helpful. Of course, you don't have to follow the recommendations if your preferences differ from the author's, but they're well thought out, and will work well for the majority of D800 users.