Microbial responses to acidic and alkaline pH are important in many areas of bacteriology. For example, the mechanisms of resistance to acidic pH are important in the understanding of the passage of human pathogens through the acid of the stomach; and an understanding of microbial degradation of alkaline industrial waste is important for the environment. Bringing together contributions from an international and interdisciplinary group of experts working on the many aspects of bacterial cellular responses to pH, this stimulating volume draws together new and innovative work in this area. It delineates both similarities and differences between mechanisms of tolerance and response, providing readers with an invaluable resource on the subject.