A vast number of biologically important enzymes, transporters, and other molecules require the participation or transport of protons. Because the proton is unique in many respects, its properties and reactions are often quite distinct from those of other ions. Our goal is to include a truly international spectrum of speakers and attendees. The invited speakers include chemists, structural biologists, and physiologists whose expertise encompasses a wide range of topics that are all related to the proton. We hope to encourage new understandings on levels from basic science to biomedical applications.