A second edition of the book (entitled “Biochemical Oscillations and Cellular Rhythms. The molecular bases of periodic and chaotic behaviour”, published by Cambridge University Press in 1996, and in paperback edition in 1997 (see Biochemical Oscillations and Cellular Rhythms) will be prepared. The book is devoted to the study of the molecular bases of cellular rhythms by means of mathematical models closely related to experimental observations. Much work has been done in this field, owing to rapid developments in Systems Biology during the last decade. Besides revising the various chapters to take into account work done since the publication of the first edition, major extensions will be made to the chapters devoted to circadian oscillations and to the cell cycle. Models for the mammalian circadian clock will be used to address physiological disorders of the sleep-wake cycle in humans, and a new chapter devoted to recently discovered cellular rhythms is planned.