Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 176. With the search for extra-solar planets in full gear, it has become essential to gain a more detailed understanding of the evolution of the other earth-like planets in our own solar system. Space missions to Venus, including the Soviet Veneras, Pioneer Venus, and Magellan, provided a wealth of information about this planet' enigmatic surface and atmosphere, but left many fundamental questions...