Addy Osmani is a Senior Staff Engineering Manager working on Google Chrome. He leads up teams focused on making the web fast and low-friction to build on for developers. Addy has authored a number of books and has spoken at conferences around the world.
Heed the warning in "Target Audience": "Some of the concepts covered (closures, prototypal inheritance) will assume a level of basic prior knowledge and understanding." That is: when you read the words closure and prototypal inheritance, it should be as though they said sandwich, or wall. You should just know what they are without thinking much about it, because this book uses terms like those (and AMD-compliant, and object literal) to explain more complex subjects. So this book is "For Beginners" at JavaScript Design Patterns, but I suspect you'd need pretty solid JavaScript expertise to get everything out of it that it has to offer.