Hidden beneath the sterile surface of Earth's neighboring planet may be the keys to unlocking the origins of life in the universe. An expert on extreme-life environments, Malcolm Walter argues that the best place to find evidence of life on Mars is out of reach of telescopes and space probes--it's in the rocks and subsurface water of the Red Planet. In this engaging and authoritative book, Walter unveils his dramatic plan-already adopted by NASA--for finding these elusive traces of life.