Absolutely, it is really the 101 of JavaScript and helps you avoid a lot of the pitfalls that gave the language a bad name for so many years.
JavaScript: the definitive guide, is also a good book.
Object-Oriented JavaScript: Create scalable, reusable high-quality JavaScript applications and libraries.
As well most all of John Resig books are good.
On the other hand it was one of the shortest book I ever read in which I had to reread and go back more times. JavaScript can be a bit confusing at times and the book only says things once and in a succinct way.
Everything was going fine until Prototypes and Constructors and the very bad 'new' operator, that somewhat surprisingly was used in the good function which achieved Prototype Inheritance (example in here: http://javascript.crockford.com/prototypal.html), but after a while I got it. ;)
It's the only book I've read about JavaScript yet. I consider it very good if you already are proficient in other programming languages, but it doesn't really show you what to do with it (and it wasn't supposed to), so I'm now planing to buy JavaScript the Definitive Guide.
Crockford also has some interesting articles at: http://javascript.crockford.com/