In this episode I speak to Julian Davies, professor emeritus in the Department of Microbiology & Immunology at the University of British Columbia.

Dr. Davies is one of the world's experts on antibiotics. I talked to Davies about how the discovery of antibiotics changed the course of modern medicine, and how we now face a growing threat from the evolution of antibiotic-resistant bacteria. We also talked about some enduring mysteries about antibiotics.

Most of us think of antibiotics as a way to kill microbes. But the fact is that microbes make antibiotics naturally, and for them, these molecules may not be lethal weapons. They may actually be a way to talk to other microbes.