The concept that circadian rhythmicity and redox state are necessarily and intimately linked is widely accepted. This volume presents evidence in support of this view, emphasizing the crucial importance and role of antioxidative protection. The overview provides a neat synopsis of each of the specialist contributions. Moreover, it provides a unique personal perspective on the essential ideas presented in each chapter, taking the conclusions even further to provide an integrated view. This makes the overview very interesting reading indeed. The second chapter concerns the essential features of redox reactions and the concept of a cellular ‘redox state’. This chapter gives fundamental, important information. The term ‘redox state’ is frequently found in the literature but is often used loosely and sometimes even incorrectly. The authors of Chapter 2 draw attention to the importance of the Nernst equation as this dominates the estimation of redox state, and they point out the key role of oxygen in cellular redox reactions. The third chapter concerns the thioredoxin system in plant cells. This chapter emphasizes the central role of thioredoxins in photosynthesis, which by its very nature distinguishes plant thioredoxin biochemistry from that found in other organisms. No clear evidence for interactions between the glutathione and thioredoxin systems has been found in plants where these physiologically important redox thiols appear to operate more or less independently. The role of thiols in the regulation of the cell cycle is explored in Chapter 4. This very short chapter gives basic details concerning the hypothesis that cyclic inter‐conversion of dithiols and disulfides provides a central theme that unifies ultradian, cell cycle and circadian rhythms. Moving on to a very specific case where a rhythm in a major antioxidant has been demonstrated, Chapter 5 deals with the variations in melatonin. The following two chapters explore why melatonin is produced in a cyclical manner, providing evidence for a relationship between oxidative stress and circadian rhythms in a variety of organisms. Bringing together information on melatonin rhythms and their integration with other antioxidants, these chapters clearly establish the concept that antioxidants are linked to cell signal transduction and may themselves be key signals. The idea that there is a regulated periodicity in the formation of active oxygen and antioxidant protection is intriguing. Moreover, this rhythmicity may be critical to the outcome of processes such as the cell cycle where there is evidence for stage‐specific enhancement of susceptibility to oxidative stress. Key questions regarding rationale and mechanism appear repeatedly and the absence of clear answers underlines the urgent need for more research in this area. Chapter 8 presents the view that one answer may reside in the nature of plasma membrane redox phenomena. It is only relatively recently that the roles of redox reactions and electron transport capabilities of the plasma membrane have been acknowledged, particularly in plants. This chapter provides an effective and comprehensive summary of many of the key points of this function of the plasma membrane. Chapter 9 takes this further, considering the unique role of plasma membrane oxidant generation in disease resistance. Using the phagocyte leukocyte model, the authors point to the importance of circadian variation in the health/disease equilibrium. The theme of disease control is extended in Chapter 10, which explores the link between circadian control of hepatic cytochrome P‐450 monooxygenase and the observed rhythmicity in toxic live injury. In Chapter 11, the concept that circadian regulation of the redox state of the cell determines life/death scenarios is explored further. The evidence that cellular redox state not only regulates mitosis, but also apoptosis is examined and discussed. The crucial importance of this rhythmicity in determining the administration of anticancer drugs is underlined. The last two chapters deal with the role of circadian rhythmicity in plant tissue culture situations, especially the survival of explants, and the related concepts of general cell survival strategies related to adaptation to stress. The hypothesis that oxidative stress is a major driving force for evolution is explored, given the fact that many oxidants and antioxidants are key signal molecules controlling gene transcription. In summary, this is an excellent volume that I recommend without reservation to biologists in all disciplines. It is rare to find a text of this nature that makes truly enjoyable reading. Not only is this volume packed with useful information, but it also conveys much of the enthusiasm and motivation of the authors in the pursuit of the advancement of science. As such it makes compelling reading and this volume would be an asset to any scientific library.