This book targets intermediate-level frontend web developers. The book is not intended to be an introduction to web development. As such, we assume that readers have a firm grasp of the basic concepts behind web development, essential HTML, JavaScript, and CSS skills, as well as practical experience of applying this knowledge. Furthermore, the reader should have an understanding of jQuery. Elementary knowledge about AngularJS, build tools, and React are desirable for the book's final two chapters. However, unfamiliarity with the two frameworks will not stop readers from completing and understanding the examples.