Book excerpt: Until very recently, all we really knew about Venus, our nearest planetary neighbor, was that it was roughly the same size and mass as the earth and was surrounded by a thick atmosphere. Then, in 1989, American scientists launched Magellan—the spacecraft that would revolutionize our vision of this mysterious planet. Venus Revealed is the first book to explain the breathtaking results of this mission, which unveiled a Venusian world of active volcanoes, shining mountains, and river valleys carved by torrents of flowing lava. At one time, Venus may have even had a wet, temperate climate, much like Earth's. What happened to turn it into a hostile, burning acid world? The answer could very well help us solve some of our most pressing environmental problems—from global warming to acid rain. In Venus Revealed, David Grinspoon eloquently argues that studying our exotic twin will inevitable teach us more about ourselves.