Mars has always held a special interest because of the possibility that life may have existed there. The story of water on Mars is crucial for understanding the planet's geological, climatological, and biological history. In this book Dr. Carr summarizes the history of water on Mars. He highlights problems confronted, addressing them from the records of the morphology of the surface and the chemistry and mineralogy of some near-surface rocks, as revealed in meteorites originating on Mars. The book is well illustrated with imagery from the Viking missions. The water story has important implications for the future exploration of the planet.