Popular science at its most exciting: the breaking new world of chronobiology - understanding the rhythm of life in humans and all plants and animals. The entire natural world is full of rhythms. The early bird catches the worm -and migrates to an internal calendar. Dormice hibernate away the winter. Plants open and close their flowers at the same hour each day. Bees search out nectar-rich flowers day after day. There are cicadas that can breed for only two weeks every 17 years. And in humans: why are people who work anti-social shifts more illness prone and die younger? What is jet-lag and can anything help? Why do teenagers refuse to get up in the morning, and are the rest of us really 'larks' or 'owls'? Why are most people born (and die) between 3am-5am? And should patients be given medicines (and operations) at set times of day, because the body reacts so differently in the morning, evening and at night? The answers lie in our biological clocks the mechanisms which give order to all living things. They impose a structure that enables us to change our behaviour in relation to the time of day, month or year. They are reset at sunrise and sunset each day to link astronomical time with an organism's internal time.

A fascinating mine of information ... this is essential reading. * The Independent *
An intriguing and highly detailed account of circadian rhythms. * Observer *
Foster is a pioneer who takes readers on a captivating journey ... it is time that the profound knowledge of clock research reaches everyone in society; this book does an excellent job in this campaign * Nature *
Humans, like all other living creatures, live in and by time, but increasingly in our 24/7 society the deep evolutionarily conserved rhythms on which our lives have depended have become disturbed by a digitized clockwise form of time. In this accessible and richly informed book Russell Foster and Leon Kreitzman explore the meaning, significance and mechanism of these ancient biological clocks in our own day-to day lives and those too of other life forms on earth. * Professor Steven Rose *

Leon Kreitzman is a consultant and biologist and the author of 24 Hour Society. Russell Foster is professor of Biology at Imperial College, London and the world's leading expert on chronobiology.