Preface vii // Introduction // Timeline 13 // PART I: COSMOS // Chapter 1 In the Beginning: Threshold 1 17 // Chapter 2 Stars and Galaxies: Thresholds 2 and 3 39 // Chapter 3 Molecules and Moons: Threshold 4 56 // PART II: BIOSPHERE // Chapter 4 Life: Threshold 5 75 // Chapter 5 Little Life and the Biosphere 99 // Chapter 6 Big Life and the Biosphere 125 // PART III: US // Chapter 7 Humans: Threshold 6 157 // Chapter 8 Farming: Threshold 7 188 // Chapter 9 Agrarian Civilizations 210 // Chapter 10 On the Verge of Today’s World 236 // Chapter 11 The Anthropocene: Threshold 8 259 // PART IV: THE FUTURE // Chapter 12 Where Is It All Going? 287 // Acknowledgments 307 // Appendix: Statistics on Human History 311 // Glossary 313 // Further Reading 325 // Notes 327 // Index 341