Reviewers overuse the phrase 'required reading,' but no other description fits the new book 'Ajax Security' (2007, Addison Wesley, 470p). This exhaustive tome from Billy Hoffman and Bryan Sullivan places the specific security concerns of the AJAX programming model in historical perspective. It demonstrates not only new security threats that are unique to AJAX, but established threats that have gained new traction in the Web 2.0 era. It then details both the specific technical solutions and - more importantly - the mindset that are necessary to combat such threats. If you call yourself a professional web developer, you need this book.