The veteran of four space flights and the American record holder for consecutive days spent in space, Scott Kelly has experienced things very few have. Now, he takes us inside a sphere utterly inimical to human life. He describes navigating the extreme challenge of long-term spaceflight, both existential and banal: the devastating effects on the body; the isolation from everyone he loves and the comforts of Earth; the pressures of constant close cohabitation; the catastrophic risks of depressurization or colliding with space junk, and the still more haunting threat of being unable to help should tragedy strike at home--an agonizing situation Kelly faced when, on another mission, his twin brother's wife, Gabrielle Giffords, was shot while he still had two months in space.