What do we know about Mars? What remains to be understood? Is there evidence of life there? Will humans ever travel there? The dream of exploring Mars has been around since the early days of human civilization and still forms part of our vision of the future for the human race. Today, we send unmanned spacecraft to explore this neighboring world to examine its climate, search for evidence of past or present life, and learn how conditions there relate to those on Earth. Plans are now being prepared for a manned mission to Mars, set against an uncertain background of political, practical, technical and financial considerations. This unique book provides a complete description of the past, present and future of Mars exploration. Written by a scientist intimately involved with missions to Mars, it provides a personal first-hand account. It will appeal to anyone interested in this fascinating planet.