I learned Javascript from that book with around zero prior knowledge of Javascript as a programming language. So, to be more specific, I'd throw in that it's a perfectly fine book for a beginner to Javascript per se. It will probably confuse you, though, if you are not merely desiring to learn Javascript, but you are a beginner to programming in general and learning a programming language is a novelty to you in and of itself -- by the time I picked up the Crockford book, I was proficient in a variety of other programming languages and had a computer science degree.

If there is anything I could complain about, it would be at the other end of the spectrum: it ends after covering just the basics of the language itself; I don't even think it covers the browser DOM. But if you buy it at a physical bookstore, the thickness of it should tip you off as to what you're getting. As far as it goes, it's a great book.