The earth's daily rotation affects just about every living creature From dawn through to dusk there are changes in light temperature humidity & rainfall However these changes are regular rhythmic & therefore predictable Thus the near 24 hour circadian rhythm is innate a genetically programmed clock that essentially ticks of its own accord This Very Short Introduction explains how organisms can know the time & reveals what we now understand of the nature & operation of chronobiological processes Covering variables such as light the metabolism human health & the seasons Foster & Kreitzman illustrate how jet lag & shift work can impact on human well-being & consider circadian rhythms alongside a wide range of disorders from schizophrenia to obesity ABOUT THE SERIES The Very Short Introductions series from Oxford University Press contains hundreds of titles in almost every subject area These pocket-sized books are the perfect way to get ahead in a new subject quickly Our expert authors combine facts analysis perspective new ideas & enthusiasm to make interesting & challenging topics highly readable