One of Smithsonian Magazine's Ten Best Science Books of 2025 The fascinating, untold story of the air we breathe, the hidden life it contains, and invisible dangers that can turn the world upside down Every day we draw in two thousand gallons of air--and thousands of living things. From the ground to the stratosphere, the air teems with invisible life. This last great biological frontier remains so mysterious that it took over two years for scientists to finally agree that the Covid pandemic was caused by an airborne virus. In Air-Borne, award-winning New York Times columnist and author Carl Zimmer leads us on an odyssey through the living atmosphere and through the history of its discovery. We travel to the tops of mountain glaciers, where Louis Pasteur caught germs from the air, and follow Amelia Earhart and Charles Lindbergh above the clouds, where they conducted groundbreaking experiments. We meet the long-forgotten pioneers of aerobiology including William and Mildred Wells, who tried for decades to warn the world about airborne infections, only to die in obscurity. Air-Borne chronicles the dark side of aerobiology with gripping accounts of how the United States and the Soviet Union clandestinely built arsenals of airborne biological weapons designed to spread anthrax, smallpox, and an array of other pathogens. Air-Borne also leaves readers looking at the world with new eyes--as a place where the oceans and forests loft trillions of cells into the air, where microbes eat clouds, and where life soars thousands of miles on the wind. Weaving together gripping history with the latest reporting on Covid and other threats to global health, Air-Borne surprises us on every page as it reveals the hidden world of the air.