I've been following this book for a while now and I'm pretty thrilled to see its reception here on HN. This book is an excellent introduction to front-end development (and even a little backend since it does include a chapter on Node.js)

It has an excellent balance of design patterns and introductory knowledge to attract the new and also seasoned developers who are beginning to look at javascript more seriously.

(This book is also a great primer for anyone who did not understand Javascript the Good Parts)