Acknowledgments

I’d like to acknowledge all the people who have helped make this book possible, from the students who needed me to explain theory in a straight-forward manner to those of my friends and colleagues who encouraged me to write those explanations down. I’d also like to thank Debbie DuFrene, who took a chance on my idea; my daughter Celia Luck-Leonard who said the book needed illustrations; and Premkumar Narayanan, who had infinite patience with me while putting the book together.