This book is not necessarily for you if:
You have never written an HTML web page before, but you want your own website. This book is focused on how to use ExpressionEngine, not on how to write HTML. Although you may be able to follow the book's step-by-step instructions, knowledge of HTML/CSS will allow you a better appreciation of how the example website is put together.
You want to learn advanced website building techniques and technologies such as AJAX, JavaScript, or PHP. This book does not set out to teach these things. However, anything that you learn from other books and tutorials on these subjects can be easily applied to a website powered by ExpressionEngine. The sky is the limit.
You have extensive experience in ExpressionEngine, but want to learn advanced tips and tricks such as add-on development. This book is intended as an introduction for new users to ExpressionEngine. That said, experienced users may pick up some new ideas or ways to do things — every ExpressionEngine user does things slightly differently.
You want a definitive guide to ExpressionEngine. As a printed book, it is almost a given that ExpressionEngine will have changed since this book was written. This book is meant more as a springboard into your own exploration of what ExpressionEngine can do and does not attempt to cover every available feature.