Hydrothermal venting of mid-ocean ridges has become one of the fstest-growing areas of interest in the marine geosciences since their discovery at the beginning of the 1980s. Marine geologists, geochemists and biologists are beginning to unravel th eprocesses that generate and focus these high-temperature, chemically charged fluid exhalations, and those that control the colonisation and ecology of the bizarre gamut of fauna and flora resident at these sites. The papers in this volume represent the latest reviews and reports on this subject.