the United States of America The paper used in this book complies with the Permanent Paper Standard issued by the National Information Standards Organization (Z39.48-1984). 10 9 8 7 6 5 4 3 2 1 To our grandchildren Annika, Jacob, Katherine, Madison, Magnus, and Molly Contents Illustrations . . . . . Preface . . . . . . . . . Acknowledgments . The Web Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .