Exploring Historical Breakthroughs in Human Life Expectancy and Health Improvements

Today, friend-of-the-pod Steven Johnson stops by to share a few big ideas from his recent book "Extra Life," which President Obama praised for offering readers "a useful reminder of the role of modern science in fundamentally transforming all of our lives."

• If you enjoy this episode, check out the audio essay we made with Steven. It's called "Immortality: A User's Guide"