The book covers Drupal 5, from creating a basic module to in-depth documentation of the menu system and form API. Many heavy hitters in the Drupal community contributed to the book by reviewing drafts and offering suggestions and improvements. Among them were Károly Négyesi, Steven Wittens, Angela Byron, Heine Deelstra, John Resig, Ted Serbinski, Nathan Haug, Jeff Eaton, Gábor Hojtsy, and Neil Drumm. In addition to reviewing chapters, Dries wrote the foreword.