The continental shelf seas have an importance out of proportion to the reatively small fraction of the area of the global ocean which they occupy. These shallow seas play and important role as the high energy boundary zones of the deep ocean where much of the ocean's tidal and wave energies are dissipated. The North Sea is an archetypal representative of such seas. This text brings the principal results from the North Sea Project which were presented at a discussion meeting organized by the Royal Society. It argues that we should understand and predict the processes of the North Sea in order to achieve a degree of rational management in the future, as environmental threats increase.