The field of physical oceanography has matured to a point where it is now conceivable to combine numerical models and observations via data assimilation in order to provide ocean prediction products on various spatial and time scales. As a result, many nations have begun large-scale efforts to provide routine products to the oceanographic community and started to develop operational oceanography systems. The Global Ocean Data Assimilation Experiment (GODAE) provides a framework for these efforts, i.e. a global system of observations, communications, modeling, and assimilation that will deliver regular, comprehensive information on the state of the oceans, in a way that will promote and engender wide utility and availability of this resource for maximum benefit to the community. The societal benefit of this experiment will be an increased knowledge of the marine environment and ocean climate, predictive skills for societal, industrial, and commercial benefit and tactical and strategic advantage, as well as the provision of a comprehensive and integrated approach to the oceans. The chapters collected in this volume cover a wide range of topics and summarize our present knowledge in ocean modeling, ocean observing systems, and data assimilation.