This book is for people who have had some experience with JavaScript, and want to have a better, deeper understanding of how it works and how to use it well. It is also for experienced programmers who are looking to understand the workings of another language.This book is not for beginners. I hope to someday write a book for beginners. This is not that book. This is not a light book. If you skim it, you will likely get nothing from of it.This book is not about JavaScript engines or virtual machines. It is about the language itself and the things every programmer should know about it. This book is a radical reappraisal of JavaScript, how it works, how it could be made better, and how it can be better used. It is about how to think about JavaScript and how to think in JavaScript. I am going to pretend that the current version of the language is the only version. I am not going to waste your time by showing how things worked in ES1 or ES3 or ES5. That does not matter. The focus is on how JavaScript works for us now.This book is not comprehensive. There are large, complex chunks of the language that will be dismissed without a word. If I fail to mention your most favorite feature, that is most likely because that feature is crap. I will not be paying much attention to syntax. I am assuming that you already know how to write an if statement.