In 1960 Captain Joseph Kittinger fell to earth from the edge of space and survived. He stepped from the basket of a gigantic helium balloon into an appalling, hostile environment which, without the protection of a pressure suit, would have simultaneously frozen his body and boiled away his blood. And yet it is the air that Kittinger fell through that makes our lives on earth possible. We not only live in the air, we live because of it. And air is about much more than just breathing. At ground level air transforms miraculously into solid food, and without it every creature on earth would starve; it wraps our planet in a blanket of warmth; radio signals bounce off a floating mirror of metal in the air to travel round the world; and the outer layer of our atmosphere soaks up flares from the sun more violent than all the world's nuclear warheads put together.Gabrielle Walker traces a journey of groundbreaking scientific discovery, from the Italian Renaissance scientist Torricelli, disciple of Galileo, who realised that we live at the bottom of a dense ocean of air, to the West Virginian farmhand William Ferrel, who unlocked the secrets of the trade winds by making calculations with a pitchfork on the back of a barn door. Then there is the hapless 1920s inventor Thomas Midgley, who when trying to solve a refrigeration problem inadvertently created chemicals that punched a hole in the sky, and the extraordinary American discovery at the height of the Cold War that space itself is radioactive.An Ocean of Air is a triumphant celebration of the fragile complexity of Earth's atmosphere and a completely engaging work of popular science.