I just wrapped up "Effective JavaScript" by David Herman. Subtitled, "68 Specific Ways to Harness the Power of JavaScript", the book covers nearly seventy different very specific tips focusing on:

*Language basics
*Variable scope
*Functions
*Objects and prototypes
*Arrays and dictionaries
*Library and API design
*Concurrency

Each tip is pretty intense in terms of detail, but the author wraps things up with a few bullet points to help you really get the point. This is not another framework book, but instead focuses on core language concepts. Frankly, it is a bit overwhelming, but it really works well if you read a few tips at a time. It also makes it easier to come back to later for review. I plan on keeping this one nearby. I can definitely recommend it, but for folks still new to the language, expect to take it a bit slowly at first.