Scientists and enthusiastic amateurs first confirmed the existence of living things invisible to the human eye in the late sixteenth century. So why did it take two centuries to connect microbes to disease? As late as the Civil War in the 1860s, most soldiers who perished died not on the battlefield but of infected wounds, typhoid, and other diseases. Twenty years later, the outcome might have been different, following one of the most radical intellectual transformations in history: germ theory, the recognition that the tiniest forms of life have been humankind’s greatest killers. It was a discovery centuries in the making, and it transformed modern life and public health.

As today’s guest, Thomas Levenson (author of “So Very Small: How Humans Discovered the Microcosmos, Defeated Germs—and May Still Lose the War Against Infectious Disease”) reveals in this globe-spanning history, it has everything to do with how we see ourselves. For centuries, people in the West, believing themselves to hold dominion over nature, thought too much of humanity and too little of microbes to believe they could take us down. When nineteenth-century scientists finally made the connection, life-saving methods to control infections and contain outbreaks soon followed. The next big break came with the birth of the antibiotic era in the 1930s. And yet, less than a century later, the promise of the antibiotic revolution is already receding due to years of overuse. Is our self-confidence getting the better of us again?

So Very Small follows the thread of human ingenuity and hubris across centuries—along the way peering into microscopes, spelunking down sewers, visiting army hospitals, traipsing across sheep fields, and more—to show how we came to understand the microbial environment and how little we understand ourselves. Levenson traces how and why ideas are pursued, accepted, or ignored—and hence how human habits of mind can, so often, make it terribly hard to ask the right questions.

Scientists and enthusiastic amateurs first confirmed the existence of living things invisible to the human eye in the late sixteenth century. So why did it take two centuries to connect microbes to disease? As late as the Civil War in the 1860s, most soldiers who perished died not on the battlefield but of infected wounds, typhoid, and other diseases. Twenty years later, the outcome might have been different, following one of the most radical intellectual transformations in history:&nbsp;germ&nbsp;theory, the recognition that the tiniest forms of life have been humankind&rsquo;s greatest killers. It was a discovery centuries in the making, and it transformed modern life and public health. As today&rsquo;s guest, Thomas Levenson (author of &ldquo;So Very Small: How Humans Discovered the Microcosmos, Defeated&nbsp;Germs&mdash;and May Still Lose the War Against Infectious Disease&rdquo;) reveals in this globe-spanning history, it has everything to do with how we see ourselves. For centuries, people in the West, believing themselves to hold dominion over nature, thought too much of humanity and too little of microbes to believe they could take us down. When nineteenth-century scientists finally made the connection, life-saving methods to control infections and contain outbreaks soon followed. The next big break came with the birth of the antibiotic era in the 1930s. And yet, less than a century later, the promise of the antibiotic revolution is already receding due to years of overuse. Is our self-confidence getting the better of us again? So Very Small&nbsp;follows the thread of human ingenuity and hubris across centuries&mdash;along the way peering into microscopes, spelunking down sewers, visiting army hospitals, traipsing across sheep fields, and more&mdash;to show how we came to understand the microbial environment and how little we understand ourselves. Levenson traces how and why ideas are pursued, accepted, or ignored&mdash;and hence how human habits of mind can, so often, make it terribly hard to ask the right questions.

For history lovers who listen to podcasts, History Unplugged is the most comprehensive show of its kind. It's the only show that dedicates episodes to both interviewing experts and answering questions from its audience. First, it features a call-in show where you can ask our resident historian (Scott Rank, PhD) absolutely anything (What was it like to be a Turkish sultan with four wives and twelve concubines? If you were sent back in time, how would you kill Hitler?). Second, it features long-form interviews with best-selling authors who have written about everything. Topics include gruff World War II generals who flew with airmen on bombing raids, a war horse who gained the rank of sergeant, and presidents who gave their best speeches while drunk.

A show about American history, world history, World Wars 1 & 2, the Civil War, and much more.

History Unplugged Podcast

For history lovers who listen to podcasts, History Unplugged is the most comprehensive show of its kind. It's the only show that dedicates episodes to both interviewing experts and answering questions from its audience. First, it features a call-in show where you can ask our resident historian (Scott Rank, PhD) absolutely anything (What was it like to be a Turkish sultan with four wives and twelve concubines? If you were sent back in time, how would you kill Hitler?). Second, it features long-form interviews with best-selling authors who have written about everything. Topics include gruff World War II generals who flew with airmen on bombing raids, a war horse who gained the rank of sergeant, and presidents who gave their best speeches while drunk.