5/6 A look at the unsung heroes who allowed us to transport our voices over long distances.
4/6 A look at the unsung heroes of invention in the surprising journey from candle to laser.
3/6 Steven Johnson traces the unsung heroes behind the modern skill of making cold.
2/6 Steven Johnson discovers the surprising journey of time in our lives.
1/6 Steven Johnson traces the journey from dirty to clean in our lives.