This book about, ""clocks"" of all sorts is at one and the same time fascinating and confusing. Generally it can be described as an informed account of timed biological patterns which could create an awareness of the pervasiveness of rhythmic patterns in our environment. The content ranges from the common ""time"" notion to less familiar but interesting and important rhythms in the biosphere including those that govern and/or accompany hibernation, pupal development of insects and cell division. But the account wanders from time to time to consider in an equally interesting manner topics hardly related to the scope of the book (gravity organs used by some floating animals to detect up and down). This suggests comparison with Margaret Hyde's Animal Clocks and Compasses which includes such examples without missing the focus. The Hyde book is as interesting and more integrated if somewhat more advanced in reading level.