On January 24, I discussed a not-very-focused book on Ajax, and mentioned its diversion to a discussion of Rails: "Near the end of the journey, we detour to Ruby on Rails, and finally get to its Ajax support; I'm not completely sure why Woychowsky bothered with that particular side trip." And now for something completely different: a pleasant surprise. Scott Raymond's new book Ajax on Rails (O'Reilly, “Near the end of the journey, we detour to Ruby on Rails, and finally get to its Ajax support; I’m not completely sure why Woychowsky bothered with that particular side trip.”And now for something completely different: a pleasant surprise. Scott Raymond’s new book Ajax on Rails (O’Reilly, 2007, 336 pp., $39.99, ISBN 0-596-52744-6) discusses Ajax and Ruby on Rails, focusing on the Ajax support in Ruby on Rails in just about the right depth for most developers, and offering some valuable insight without going too far afield.Scott is a Rails insider: he’s one of the developers of the framework. His book has the unmistakable ring of experience, and it is well-organized and well-written. The chapter on RJS (Ruby-generated JavaScript) is especially welcome, but his chapter on debugging and testing Rails is quite valuable, and his chapters on Rails security and performance will help people lock down and tune up their applications.I’m not sure how much value the extensive references to the Prototype and script.aculo.us JavaScript libraries will have for Rails developers. Is this just dross to get the page count up, or is it useful? I’ve done enough JavaScript development that I might come down on the “merest dross” side of the argument, but there may well be Ruby developers for whom JavaScript is enough of a mystery to justify the space spent on this reference material. Software Development