Antibiotics revolutionized medicine. Infections that were once severe, even fatal, can now be treated. But the dark ages could return. The reason? Overuse. We are in an arms race with antibiotic-resistant bacteria, and we seem to be losing. Every year, 2 million Americans are infected with these nightmare microorganisms. At least 23,000 people die. The numbers are even more dire in some regions of the world. In fact, modern medicine itself may be in peril. One day not too far off, injuries that become infected could lead to death, as in the days before the discovery of penicillin. Who is to blame? And what’s to be done?