jQuery Fundamentals - An excellent and free book for learning jQuery

If you've been trying to learn (or learn more about) jQuery, and you don't know about Rebecca Murphey's excellent Creative Commons licenced book jQuery Fundamentals, you're missing out.

It starts with a gentle introduction to the basics of JavaScript before delving into the nitty-gritty of jQuery, with chapters covering the basics, events, effects, AJAX, plugins, and best practices.

jQuery Fundamentals, available in HTML, PDF, and ePUB versions.