Your body contains a symphony of tiny timepieces, synchronised to the sun and subtle signals in your environment and behaviour. But modern insults like artificial light, contrived time zones and late-night meals can wreak havoc on your internal clocks. Armed with advances in biology and technology, a circadian renaissance is reclaiming those lost rhythms. The Inner Clock explores the emerging science and its transformative applications: How could taking a walk in the morning and going to bed at the same time each night keep your body in sync? Why are some doctors prescribing treatments at specific times of day? And how might a better understanding of our circadian rhythms improve educational outcomes, optimise sports performance, and support the longevity of our planet? Science journalist Lynne Peeples seeks out the scientists, astronauts, athletes and patients at the forefront of a growing movement. Along the way, she sleeps in a Cold War-era bunker, chases the midnight sun, spits into test tubes, and wears high-tech light sensors to decipher what makes our internal clocks tick and how we can reset them for the better.