This is an invaluable textbook, prepared by the Open University team and designed so that it can be read on its own or as part of the OU course. This second edition has been fully revised and updated including new colour illustrations increasing the striking spread of full colour diagrams throughout the book. The clarity of the text has been improved, providing comprehensive coverage of the evolution of ocean basins and their structure in a clear, concise manner aimed specifically at the student market. This second edition provides the technological advances in fields as diverse as: deep-towed instruments for 'sniffing' hydrothermal plumes; mapping the sea-floor by sophisticated sonar techniques; three-dimensional imaging of crustal structure by seismic tomography; the use of satellites for navigation, and for making precise measurements of the height of the sea-surface. The first chapters describe the processes that shape the ocean basins, determine the structure and composition of oceanic crust and control the major features of continental margins. How the 'hot springs' of the oceanic ridges cycle chemical elements between seawater and oceanic crust is then explored. Sediment distributions are examined next, to demonstrate how sediments can preserve a record of past climatic and sea-level changes. Finally, the role of the oceans as an integral part of global chemical changes is reviewed. It includes: high quality full colour diagrams; substantial chapter summaries ideal for revision; and answers, hints and notes for questions at back of the book.