Public sanitation and antibiotic drugs have brought about historic increases in the human life span; they have also unintentionally produced new health crises by disrupting the intimate, age-old balance between humans and the microorganisms that inhabit our bodies and our environment. As a result, antibiotic resistance now ranks among the gravest medical problems of modern times. Good Germs, Bad Germs tells the story of what went terribly wrong in our war on germs. It also offers a hopeful look into a future in which antibiotics will be designed and used more wisely, and beyond that to a day when we may replace antibacterial drugs and cleansers with bacterial ones.