| 1. Leeuwenhoek Discovers a New Galaxy of Organisms | 1 |
| 2. The Microbial Kingdom Has Many Subjects | 9 |
| 3. Some Microbes Prefer Life Without Air | 13 |
| 4. Important Molecules in Microbes, Plants, and Animals | 19 |
| 5. How Microbes are Isolated and Identified | 33 |
| 6. The Care and Feeding of Microbes | 45 |
| 7. Hardy Survivors in the Microbial Kingdom | 53 |
| 8. Microbes and the Carbon Cycle | 62 |
| 9. Bacteria That Produce and Use Methane | 72 |
| 10. Microbes Recycle Nitrogen | 82 |
| 11. Bacteria Spin the Sulfur Cycle | 91 |
| 12. An Amazing Diversity of Lifestyles | 95 |
| 13. Bioenergetics: "Energy Currency" | 116 |
| 14. The Role of Vitamins | 129 |
| 15. Microbes and Sewage Treatment | 135 |
| 16. Plagues and the Origin of the Germ Theory of Disease | 144 |
| 17. Three Giants of Infectious Disease Research: Pasteur, Koch, and Jenner | 153 |
| 18. Mechanisms of Immunity | 161 |
| 19. Viruses Confound Microbe Hunters | 175 |
| 20. The Control of Microbial Disease | 181 |
| 21. The Role of DNA and New Vistas in Microbial Technology | 187 |
| 22. Coda: Microbes and Early Life on Earth | 207 |
| Appendix I | |
| How Leeuwenhoek Estimated the Sizes of Microbes | 212 |
| Appendix II | |
| Microbes in the American Type Culture Collection | 215 |
| Appendix III | |
| Microbes in Early Science Fiction | 217 |
| Appendix IV | |
| The Ingenious Use of Microbiology Under Adverse Conditions | 222 |
| Who's Who in This Book | 228 |
| Suggestions for Further Reading | 232 |
| Glossary | 236 |
| Credits and Acknowledgments | 241 |
| Index | 243 |