Twenty years after the Viking missions of the '70s, we are finally going back to Mars. No fewer than ten missions are planned for the period between 1996 and 2003, and it is likely that human explorers will follow soon after--perhaps by the middle of the twenty-first century. When they do, they will owe much to the Mars of romance, to the early pioneers whose discoveries and disappointments are brought to life in The Planet Mars: A History of Observation...