This text presents a description of Mars's biology and biological potential since 1997's announcement of life in a Martian meteorite. What few people realize, however is that Viking Lander laboratory experiments on the Martian surface arranged by bioengineer and chemist Dr Gilbert V. Levin in 1976 showed clear indications of life on Mars. NASA disputed these results, and only now have Levin's files been opened to the public eye. This text not only traces a search for alien life forms, but it is also an encyclopaedia of current knowledge of the Martian landscape and biosphere, its history, and its potential for sustaining life.