A Leanpub Community Edition is part or all of a Leanpub book which the authors are providing to you for free, in exchange for you sharing your email address with them. Leanpub is a self-publishing platform, and our Community Edition feature allows authors to make everything from one chapter to the entire book available for free. We don't earn any money from it, and we provide the feature so that authors can offer subsets of their books in exchange for email addresses.