This is a very beginner book for people who want to learn to code. It has been downloaded by over 300 thousand people since the 1st Edition last year. If you can already code then the book will probably drive you insane. It's intended for people who have no coding chops to build up their skills before starting a more detailed book. The 2nd Edition features 5 new exercises, fixes and updates to nearly every exercise, and three of the new exercises teach you to create a simple web application as the final part of the book.