Dr. Marie Lodén was appointed Associate Professor in Experimental Dermatology at Uppsala University in 2005 and is the founder and owner of the Eviderm Institute, Sweden, which is devoted to dermatological research and product development. Dr. Lodén previously conducted dermatological research on chemical warfare agents and worked on the development of topical treatments at pharmaceutical and cosmetics companies. Her major research interests are skin barrier function, contact dermatitis, skin care, biophysical measurements, and toxicology. She has edited previous books and published almost 100 original papers and reviews. Howard I. Maibach is Professor of Dermatology at the University of California, San Francisco. He is a leading authority in the fields of dermatotoxicology and dermatopharmacology, in which he has conducted much original research and written very extensively. Professor Maibach has served on the editorial boards of more than 30 scientific journals and is a member of many professional societies, including the American Academy of Dermatology and the International Commission on Occupational Health.