A great compendium about the Good Parts of the Javascript programming language, written by the Author of JSON, Douglas Crockford. Most often noted for its thinness:
Though I personally find those syntax diagrams a little weird, they are helpful to understand and abstract the way methods are constructed. Most importantly – though it is a thin book – it covers two more areas in the back, the “bad parts” and the “ugly parts” in which Douglas Crockford covers really bad language design decisions and how to avoid these pitfalls. A must-read for anyone writing Javascript EVER.