Helmut Sies, M.D., Ph.D.(hon), studied medicine at the Universities of Tübingen, Paris and Munich, and did the habilitation for physiological chemistry and physical biochemistry at the University of Munich. He spent sabbaticals at the University of Buenos Aires, Argentina, University of California at Berkeley, USA, at the University of Siena, Italy, and the Heart Research Institute, Sydney, Australia. He was chair of the Department of Biochemistry and Molecular Biology I at Heinrich-Heine-University Düsseldorf, Germany, where he now is an emeritus professor. He also is senior scientist at the Leibniz Research Institute for Environmental Medicine at Düsseldorf, and adjunct professor at the University of Southern California, and a professor of biochemistry at King Saud University, Riyadh, Saudi-Arabia. He served as president of the Society for Free Radical Research International and of the Oxygen Club of California (OCC). He is a Fellow of the National Foundation for Cancer Research (NFCR), Bethesda, MD, USA, and of the Royal College of Physicians (FRCP), London, England. He is member of the German National Academy of Sciences Leopoldina. His research interests include hydrogen peroxide metabolism, oxidative stress, redox signaling and micronutrients, notably flavonoids, carotenoids and selenium. Regina Brigelius-Flohé received her PhD in Biochemistry in Tübingen and Münster, Germany in 1978. During a post-doctoral fellowship in Munich and Düsseldorf together with Helmut Sies she investigated the cellular thiol-disulfide status in perfused organs under various conditions of oxidative stress. The detection and analysis of mixed disulfides of proteins and glutathione provided a basis for the regulation of enzyme activities by thiol modification, a field which is now expanding and known as redox regulation. In 1984 changed to pharmaceutical industry and was heading a Molecular Biology Lab and later the Department of M