Carbon dioxide, bicarbonate ion, and carbonate ion comprise the most important acid-base system in natural waters, and the equilibria between them regulate the pH of seawater, as well as most rainwater, stream water, river water, and groundwater. This book provides a clear, compact presentation of this topic, which is central to geochemistry and environmental engineering. It emphasizes a rigorous mathematical and thermodynamic basis for calculations and their application to realistic problems. The book's first four chapters present the basic equations, mathematical techniques for visualizing and manipulating them, and data on equilibrium constants and activity coefficients. These are presented in the general context of acid-base titration and solubility of CaCO3. The remaining chapters show how these concepts and techniques are applied to geochemistry and oceanography, in addition to the applications to water conditioning. Specific topics discussed include acid rain, freshwater, seawater, carbonate sediments in the deep oceans, the effects of increased atmospheric CO2 on the oceans, estuarine waters, brines, hydrothermal solutions, pH adjustment, prediction of calcium carbonate saturation, corrosion inhibition nd water softening. Professionals and students in earth and planetary sciences, oceanography, geology, atmospheric chemistry, marine chemistry, water chemistry and environmental engineering should find this book useful.