Contributors. An Ancient Cellular Mechanism in the Tension Field between Energy Requirements and Destruction Avoidance; R. Hardeland. Overview; Th. Vanden Driessche. The Biochemistry of Redox Reactions; G.M. Petiau, et al. Light-Dark and Thioredoxin-Mediated Metabolic Redox Control in Plant Cells; H. Follmann. Redox Cycling of Intracellular Thiols: State Variables for Ultradian, Cell Division Cycle and Circadian Cycles? D. Lloyd, D.B. Murray. Occurrence and comparative physiology of melatonin in evolutionary diverse organisms; I. Balzer, et al. Circadian Rhythms and Oxidative Stress in Non-vertebrate Organisms; R. Hardeland, et al. Circadian Aspects of the Cellular Redox State: Melatonin Actions and Implications for Oncogenesis; R.J. Reiter. Plasma membrane electron transport and the control of cellular redox status and circadian rhythms; H. Asard, et al. Fluctuation of Reactive Oxygen Species Released by Inflammatory Cells; M.R.P.L. Brigagão, et al. Circadian variations in toxic liver injury and the hepatic P-450 monooxygenase system; Y. Motohashi, Y. Miyazaki. Apoptotic Signals: Possible Implication of Circadian Rhythms; C. Rodríguez, et al. Redox capacities of in vitro cultured plant tissues: the case of hyperhydricity; T. Franck, et al. Redox state and phosphorylation potential as macroparameters in rhythmic control of metabolism - a molecular basis for seasonal adaptation of development; E. Wagner, et al. Index.