If you take a quick look at the table of contents， you will see that this book is divided into five parts。These parts are not so much devoted to different topics， but rather reflect the intended evolution of the reader from the beginner working with App Inventor for the first time to the developer of advanced and complex apps—which we certainly hope will occur while you are reading this book and working through the chapters。 This structure emphasizes the tutorial nature of this text， thus we recommend reading and working through the chapters in order。 Even if you have previous knowledge of and experience with App Inventor，you should at least skim through the first few chapters to make sure you have the knowledge base that is essential for understanding the topics covered in later chapters。