The technical challenges of a human expedition to Mars are the principal theme to be explored by Martin Turner in Expedition Mars. The author begins by describing how the very latest rocket propulsion and spacecraft technology, and planned developments in nuclear and electric propulsion technologies, are the key factors which will enable a human expedition to Mars to take place. Of particular importance are the challenges of transporting cargo to Mars and in providing necessary life support for the crew, including the supply of consumables, such as food, water, air and fuel, for the return journey. In this regard the author considers how the International Space Station fits into the strategy for a human journey to the Red Planet, in its preparation of astronauts for long-duration spaceflight and the possible hazards posed by space radiation and prolonged weightlessness. The author discusses the relative merits of fast and slow journeys to Mars, i.e. is quicker also safer and cheaper? Also of importance is the role of unmanned robotic explorers in preparing the ground for human activities on Mars and in defining what the surface of Mars is like. The means by which future explorers will live and work on Mars are also explored, including issues such as habitation, modules, Mars buggies, spacesuits, scientific experiments and communications with Earth. He concludes by looking at the possible political obstacles to such a journey, but points out that sooner or later humans will have to make a choice; stay here on Earth or explore the Solar System beyond. One route takes us nowhere, the other leads to the stars.