You Don't Know JS is not just one book but there are six of them. They are ordered below from the first to the last.
You Don't Know JS: Up & Going
The first book "Up & Going" is mostly focusing on the basic building blocks of programming, and it is great for absolute beginners in programming. Up & Going will introduce you to things like operators, types, variables, conditionals, loops, functions, etc.
You Don't Know JS: Scope and Closures
You Don't Know JS: this & Object Prototypes
You Don't Know JS: Types & Grammar
You Don't Know JS: Async & Performance
The fifth book Async & Performance focuses on asynchronous features and performance tweaks which include the usage of Promises, generators, and Web Workers, which let you create modern single-page web applications. This book is my personal favorite.
You Don't Know JS: ES6 & Beyond
The last book of the You Don't Know JS called ES6 & Beyond focuses on the modern part of the language. Here you will learn the ES6 syntax that will make your life much easier. You will take a look at how to organize your code with iterators, generators, modules, and classes.
You can check You Don't Know JS books on the links below: