With poetic precision and grace, Sarah Stewart Johnson traces the evocative history of our explorations of Mars. She interlaces her personal journey as a scientist with tales of other seekers—from Galileo to William Herschel to Carl Sagan—who have scoured this enigmatic planet for signs of life and transformed it in our understanding from a distant point of light into a complex world. Ultimately, she shows how its story is also a story about Earth: it is a foil, a mirror, a tell-tale reflection of our own anxieties and yearnings to find—if we're lucky—that we're not alone.