This book explains inheritance, both classical and prototypal, and shows how it can be implemented in JavaScript. It also shows how object programming (OP) opens a new world of design possibilities that go far past inheritance. Classical OOP is only a subset of full OP. This book will help the intermediate JavaScript programmer learn to use both types of inheritance. For classical inheritance, it is accompanied by a substantial online system (a windowing UI library) that shows classical inheritance at its best. The same system shows how OP "capabilities" can elminate much of the need for inheritance. For experienced JavaScript programmers, this book shows why most of the old views of JavaScript's inheritance are wrong. JavaScript classes inherit from JavaScript's prototypes, a fact that makes JavaScript's prototypes, when used correctly, functional equivalents to C++ classes (not to prototypes in true prototypal languages, like Self). JavaScript's object programming (not inheritance) is what separates it from classical OOP languages like C++ and Java. Most important, basing inheritance on JavaScript's prototypal chain is possible, but is not the best choice for prototypal inheritance or classical inheritance.