Professional Javascript for Web Developers
By Nicholas C. Zakas

Okay, not a book for entertainment (unless you’re a bit odd) but so good I thought it deserved a mention. What can I say. Modern, thorough, well thought and dealing with practical problems – not those of image rollovers and noddy stuff, but deeper things, such as dealing with cross browser differences in event handling, etc.. Goes into depth on the DOM and XML, coding styles and the ‘inheritance’ model of Javascript. In short, the kinds of things professionals trying to build ‘Googlesque’ user interfaces will need. It’s not a reference manual, and it’s not really a ‘cook book’, it’s something in between, and it is the best technical read I’ve come across for a while!