Explains what is known about hydrothermal systems in terms of their deep-sea environment and their geological and chemical makeup. This book explores the possibility that life originated at hydrothermal vents, a hypothesis that has had impact on our ideas about the potential for life on other planets or planetary bodies in our solar system. "I heartily recommend it to anyone with an interest in learning about what is undoubtedly one of the most important discoveries in earth and life sciences of the past century."---John Woodside, The Leading Edge