“Offers a useful reminder of the role of modern science in fundamentally transforming all of our lives.” —President Barack Obama (on Twitter) “An important book.” —Steven Pinker, The New York Times Book Review The surprising and important story of how humans gained what amounts to an extra life, from the bestselling author of How We Got to Now and Where Good Ideas Come From In 1920, at the end of the last major pandemic, global life expectancy was just over forty years. Today, in many parts of the world, human beings can expect to live more than eighty years. As a species we have doubled our life expectancy in just one century. There are few measures of human progress more astonishing than this increased longevity. Extra Life is Steven Johnson’s attempt to understand where that progress came from, telling the epic story of one of humanity’s greatest achievements. How many of those extra years came from vaccines, or the decrease in famines, or seatbelts? What are the forces that now keep us alive longer? Behind each breakthrough lies an inspiring story of cooperative innovation, of brilliant thinkers bolstered by strong systems of public support and collaborative networks, and of dedicated activists fighting for meaningful reform. But for all its focus on positive change, this book is also a reminder that meaningful gaps in life expectancy still exist, and that new threats loom on the horizon, as the COVID-19 pandemic has made clear. How do we avoid decreases in life expectancy as our public health systems face unprecedented challenges? What current technologies or interventions that could reduce the impact of future crises are we somehow ignoring? A study in how meaningful change happens in society, Extra Life celebrates the enduring power of common goals and public resources, and the heroes of public health and medicine too often ignored in popular accounts of our history. This is the sweeping story of a revolution with immense public and personal consequences: the doubling of the human life span. Praise for Extra Life : “Fascinating.” — The Wall Street Journal “Offers a useful reminder of the role of modern science in fundamentally transforming all of our lives.” —President Barack Obama (on Twitter) “Fascinating story.” —Fareed Zakaria on Fareed Zakaria GPS “To call this timely would be something of an understatement.” —The Toronto Star    “Extra Life could not be timelier.” —Science Magazine “[Extra Life] gives important insight into the history of a few specific leaps and bounds we’ve made as a species to outwit disease, famine and even the safety threats posed by our own inventions.” —Discover Magazine “Johnson is a fine storyteller. . . . Extra Life is an important book.” —Steven Pinker, The New York Times Book Review “A surprising look at why humans are living longer. . . Entertaining, wide-ranging, and—in light of COVID-19—particularly timely.” — Kirkus Reviews Steven Johnson is the bestselling author of thirteen books, including Where Good Ideas Come From , How We Got to Now , and The Ghost Map . He’s the host and cocreator of the Emmy-winning PBS/BBC series How We Got to Now , the host of the podcast The TED Interview, and the author of the newsletter Adjacent Possible . He lives in Brooklyn, New York, and Marin County, California, with his wife and three sons. 1   The Long Ceiling   Measuring Life Expectancy   In the spring of 1967, a sociology graduate student from Harvard named Nancy Howell took a flight from Boston to Rome with her new husband, an anthropologist named Richard Lee. After a few days in Italy, they flew to Nairobi, where they met an academic friend of Richard's and visited the Hadza tribes living in the region. From there they flew to Johannesburg,where they loaded up on supplies and socialized with a few more researchers in the area. They purchased a truck and drove north to the newly independent country of Botswana, picking up supplies in its new capital, then traveling northwest toward the swampy oasis of the Okavango Delta, recently flooded by seasonal rains. They rented a postbox in the town of Maun, the last outpost that would contain modern amenities like convenience stores and petrol stations. From Maun, they drove about 150 miles west, on unpaved roads, to the small village of Nokaneng, on the western periphery of the Kalahari Desert.   By this point in their journey, it was July in the Southern Hemisphere, but the winter precipitation that had flooded the Okavango Delta was nowhere in sight at the edge of the Kalahari. The newlyweds created a staging ground in Nokaneng, leaving behind sufficient petrol for future travels, and then set out due west across the desert, toward the Namibian border. In the end, it took them eight hours to drive sixty miles through arid terrain.   It was a grueling voyage, and in a sense, it was also a journey back in time. At the end of their eight-hour pilgrimage lay one of few regions