'Seawater' has been substantially updated in this second edition to take account of recent developments in marine science. Sections dealing with difficult physical and chemical concepts have been developed on the basis of feedback from the first edition, making this an ideal learning tool for oceanography students. Chapter 1 summarizes the special properties of water and the role of the oceans in the hydraulic cycle. The distribution of temperature and salinity in the oceans and how they influence water density and movements is then discussed. Light and sound in seawater are considered next, along with some uses of acoustics. These are followed by an examination of the composition and behaviour of dissolved constituents, including such topics as residence times, the control of pH, and redox relationships. Finally, the history of seawater and its role in global cycles is reviewed, with special reference to climatic change and the CO2 problem.