Ask HN: Essential Javascript book for deep knowledge?

I'm looking for suggestions for an in-depth Javascript book. I worked with C++ for over 10 years feel like I have a deep understanding of the language, something I'd also like to achieve with Javascript. I've been using JS for the last couple of years and have built several projects using it (plus frameworks like Knockout.js) but I feel that depth is lacking.

Any suggestions on books, courses, online resources and anything else that could help me get there would be most appreciated!