With the development of space-travel, we have begun to explore worlds beyond Earth. Ten planetary scientists describe their favorite planet, what they have discovered, and what drives them to explore. Each tells a personal story, ranging across the breadth of the solar system—from hellish Mercury to the snows of Pluto; from telescopic to robotic exploration; from adventures in Antarctica to painting planetary landscapes; from the frustration of failure to the joy of success. Worlds Beyond is the third in a series of books bringing together leading space scientists to describe their work. Our Worlds was the first of its kind in revealing the inner motivations of planetary scientists. Our Universe explored the vastness of the Universe itself. Now, with Worlds Beyond, we return to our home—the solar system—to visit those fascinating new worlds beyond our own. S. Alan Stern is Director of the Department of Space Studies at Southwest Research Institute in Boulder, Colorado. He is a planetary scientist and astrophysicist with observational and theoretical interests. Stern is an avid pilot and a principal investigator in NASA's planetary research program, and he was selected to be a NASA space shuttle mission specialist finalist. He is the author of more than one hundred papers and popular articles. He is also the author of Pluto & Charon (Wiley, 1997).