<P>For centuries, the planet Mars has captivated astronomers and inspired writers of all genres. Whether imagined as the symbol of the bloody god of war, the cradle of an alien species, or a possible new home for human civilization, our closest planetary neighbor has played a central role in how we think about ourselves in the universe. From Galileo to Kim Stanley Robinson, Robert Crossley traces the history of our fascination with the red planet as it has evolved in literature...