Ask HN: Best book for learning advanced javascript

I am a front-end developer, and over the last few years I have become a bit fuzzy on my raw-javascript skills due to a heavy reliance on jQuery. After seeing some of the amazing stuff that node/backbone/other js frameworks are accomplishing, I think its time to dive in head-first to some more advanced JS. Any suggestions for books/sites/tutorials to put me in the right direction. Much appreciated!