Aging hippies might recognize the title of this chapter from an old Buffalo Springfield song. Others will just have to ignore it, and realize that this is the first chapter in a book on sound. As you go through this book, you'll be exposed to scientific models of what sound is and how it behaves. To get started, though, we're just going to focus on what produces sound and what causes different kinds and qualities of sound—in other words, we're starting with the basics. This free selection includes the Table of Contents and Preface.