A leading historian of astronomy and a leading planetary scientist who works at the forefront of space exploration provide a comprehensive history of the solar system's most alluring planet beyond Earth. William Sheehan and Jim Bell chronicle how ancient watchers of the skies attended to Mars's red color and baffling movements, how three and a half centuries of telescopic observations added vistas and controversies around possible seas and continents and canals, and how the current era of exploration by flyby, orbiter, lander, and rover spacecraft have conjured for us the reality of a world of towering shield volcanoes, vast canyons, ancient dry riverbeds--and even possible evidence of past life. A unique collaboration between two authors on the forefront of Mars explorations, past and future, Discovering Mars provides an ambitious, detailed, and evocative account of humanity's enduring fascination with the Red Planet.