"Does life exist on Mars? The question has captivated humans for centuries, but today it has taken on new urgency. NASA plans to send astronauts to Mars orbit by the 2030s. SpaceX wants to go by 2024, while Mars One wants to land a permanent settlement there in 2032. As we gear up for missions like these, we have a responsibility to think deeply about what kinds of life may already inhabit the planet--and whether we have the right to invite ourselves in. This book tells the complete story of the quest to answer one of the most tantalizing questions in astronomy. But it is more than a history. Life on Mars explains what we need to know before we go"--Amazon.com.