Ok, people, firstly, defending the notion that this guy is protected under freedom of speech is not the same as advocating that he actually engage in the speech he has chosen. Did you actually enter adulthood thinking freedom was ALL sunshine and roses? It's costs are many and varied.
Secondly, everything that is likely to be in this book can probably be found by reading certain psychology books. Are you advocating that those authors also be arrested? Those books, I am quite certain, have led to the abuse of children, too, probably to a far greater extent than this book. Yet, these books are written with the ultimate goal of protecting children. So, if he had started out the book with the first sentence being "This book is written as a how to book, but is meant to help parents and others in authority help their children guard against predators", would you suddenly consider the work to be under constitutional protection?