This second edition retains the general structure of the first edition, buthas been updated in the light of recent oceanographic research, and improvedas a teaching text on the basis of feedback from past students and otherreaders.Notable additions include new sections addressing the topic ofnumerical modelling, and more discussion of natural oscillations in theocean-atmosphere system (previously confined to the El Nino phenomenon). Inparticular, the Chapter on the North Atlantic now includes a discussion ofthe North Atlantic Oscillation, as well as of the Great Salinity Anomaly. Inthe final Chapter, treatment of water mass formation has been updated toreflect recent ideas about the processes involved and how they relate toclimatic change over different time-scales, from decades to millennia.