This is the the 2nd edition, released March 27, 2015, in PDF, epub and mobi (Kindle) formats. The PDF file has a bookmarked table of contents for easy navigation (make sure you turn bookmarks on in your PDF reader). The epub version looks very good on (for example) iOS devices like the iPad. (The easiest way I've found to transfer it to iOS is using Google Drive; you might have to go through two l