The study of how solar and lunar related rhythms are governed by living pacemakers within organisms constitutes the scientific discipline of chronobiology. Few fields encompass the breadth of science that is associated with this subject which is at the cutting edge of fields ranging from microbial genetics to ethology to treatment of human psychiatric illnesses. To recognise that no individual could do justice to the field in writing a comprehensive text, a group of experienced editors and contributors have collaborated to produce "Chronobiology". The text begins with a general introduction to the formalisms and vocabulary which describe circadian rhythmicity, followed by an analysis of behavioural and ecological importance of rhythms and their theoretical bases. A central block of four chapters develops the comparative anatomy, physiology, genetics and molecular biology of organisms within circadian clocks. Examples from the real world and from current and classic research are included and a final chapter looks to the future by exploring six cutting edge areas of research.