Dr. Brett Finlay explains why bacterial diseases continue to be a major health problem worldwide, causing a third of the world's deaths every year. After describing how bacteria grow, reproduce, and spread, Dr. Finlay explains how antibiotics work--and why they are not always successful in stopping infection. He describes the "genetic Internet" that enables certain pathogenic bacteria or "superbugs" to "download" genes that are resistant to all available antibiotics. He also explains how vaccines—an important tool in fighting infectious diseases—are developed. Dr. Finlay concludes his talk with a look at the potential uses of pathogenomics (the genomics of bateria) in fighting infection.