At this very moment, a symphony of tiny timepieces is ticking throughout your body - in your stomach and skin, in your liver and lungs, even in your legs. Orchestrating this round-the-clock production is a master timekeeper in your brain. What happens when these circadian rhythms are out of tune? How has our modern lifestyle led to an epidemic of broken body clocks? And how can we reverse it? In The Inner Clock, journalist Lynne Peeples travels around the world to discover the ways in which our circadian clocks affect our days - and our nights. Speaking to biologists, professional athletes, surgeons, astronomers, software developers and sleep scientists, she reveals the cutting-edge research that is newly available about the powerful sway circadian rhythms have on our bodies and our cultures. Along the way, she sleeps in a Cold War-era bunker, chases the midnight sun, spits into test tubes and wears light-adjusting headsets in an effort to decipher what makes our internal timers tick and how we can reset them for the better. Threats to our body clocks abound: artificial light, air pollution, jet lag, late-night meals and a myriad of other modern insults. But we can also harness our internal rhythms to our advantage - learning the optimal time to take medication, schedule a job interview or eat dinner. The time has come to reckon with the effects of circadian cycles on our minds, bodies and societies.