No matter how much experience you have with JavaScript, odds are you don?t fully understand the language. As part of the "You Don?t Know JS" series, this concise yet in-depth guide focuses on the "this" structure in JavaScript, which should be a convenience for developers, but often acts differently than they expect because of how it relates to scope. You?ll also exam JavaScript's prototype inheritance system, which uses the same terminology as inheritance in object-oriented languages, but in fact behaves entirely differently. Like other books in this series, You Don?t Know JS: this & Object Prototypes dives into trickier parts of the language that many JavaScript programmers simply avoid. Armed with this knowledge, you can achieve true JavaScript mastery.