I took "Show HN" out of this title because requiring an email signup to get access to the content is against the spirit of the rules: https://news.ycombinator.com/showhn.html, which say that there needs to be a way for people to try it out. In the case of a book, the established way to let people "try it out" is to share a sample chapter. If you share a sample chapter on your web page, rather than just a sample page, we can put "Show HN" back. (Edit: done now.)