This book is terrible - it's incredibly frustating to use. It's worthless as a reference and I doubt that anyone has ever read it cover to cover (including the army of authors that wrote it). I have over 10 years of experience in software development in a wide variety of languages: C++, VB, Pascal, and others. What I need to know about JavaScript could probably fit in a book half this size. This book is over 1000 pages, it's poorly organized, the index is bad, and it doesn't focus on relevant facts about the language. If I want lots of prose I'll pick up a novel, not a JavaScript book.