Why can't teenagers get out of bed in the morning? How do bees tell the time? Why do some plants open and close their flowers at the same time each day? Why do so many people suffer the misery of jet lag? In this fascinating book, Russell Foster and Leon Kreitzman explain the significance of the biological clock, showing how it has played an essential role in evolution and why it continues to play a vitally important role in all living organisms.The authors tell us that biological clocks are embedded in our genes and reset at sunrise and sunset each day to link astronomical time with an organism's internal time. They discuss how scientists are working out the clockwork mechanisms and what governs them, and they describe how organisms measure different intervals of time, how they are adapted to various cycles, and how light coordinates the time within to the external world. They review problems that can be caused by malfunctioning biological clocks--including jet lag, seasonal affective disorder, and depression. And they warn that although new drugs are being promoted to allow us to stay awake for longer periods, a 24/7 lifestyle can have a harmful impact on our health, both as individuals and as a society.

拉塞尔·福斯特（Russell Foster）伦敦帝国学院医学系分子神经科学教授，生物节律方面的国际权威。

利昂·克赖茨曼（Leon Kreitzman）作家、广播员和未来学家。在本书中，他以一个生物化学家的眼光向人们描述了生物节律的科学本质。