Until recently there was a long-held belief among biologists that social activities were by and large restricted to animals, and that creatures as small as bacteria would not benefit from sociality. Thus the laws that govern the evolution and behavior of animals would not all apply to bacteria. Over the past decade we learned that bacteria are social creatures. Not only does sociality apply in the microbial world but because bacteria are easily studied in the laboratory they are excellent models for understanding the biology of social behavior. The social activities of bacterial are often critical to their success as pathogens. We have learned that bacteria are capable of the most basic elements of sociality-communication and specialized activities within groups. The presentation will focus on one type of communication system that occurs in many Gram-negative bacteria, acyl-homoserine lactone quorum sensing using Pseudomonas aeruginosa as an example. P. aeruginosa controls the expression of hundreds of genes by a communication system that has become known as quorum sensing because it enables individuals in a population to take a census of their peers. Based on the information the group can coordinate their activity (gene expression-the quorum sensing response). The quorum-sensing response is critical for virulence of P. aeruginosa and there are efforts under way to develop anti-quorum-sensing therapeutics to treat P. aeruginosa infections. At the same time information on bacterial communication was accumulating, information on the ability of bacteria to form communities of physically interacting individuals was also accumulating. These communities called biofilms appear to exhibit division of labor, and special defense systems. This presentation will address ways in which we might translate basic research on biofilms into new therapies for chronic biofilm infections. Again, as with communication, Pseudomonas aeruginosa will be used as an example. This new view of a microbial world full of social activities has led not only to new approaches towards the treatment of bacterial infections, but also to biotechnology innovation.