The field of dermatology has very much changed during the last decades. An ever-increasing knowledge about the pathogenesis of diseases of the skin has made it possible to not only better classify but also to make dermatoses better explainable and understandable. The present book exemplifies this with a very common disease, the dyshidrotic eczema of the hands. Most current textbooks still describe "dyshidrosis" as a disease of the eccrine sweat glands, as was first postulated in 1873 by T. Fox. In 1962, R. D. G. P. Simons challenged this concept and since then, it has not been possible to establish a uniform pathogenetic concept regarding "dyshidrosis". The only generally accepted view is that the dermatosis has multiple etiologies. This monograph is intended to be a follow-up to Simons' book published in 1966, entitled Eczema of the Hands. Investigations into Dyshidrosiform Eruptions. It repre­ sents an attempt to view the clinical and experimental aspects of atopic palmoplantar eczema as a basis for an understanding of the entire entity of dyshidrosis. My special thanks go to Prof. Dr. E. Macher, Miinster, who made it possible for me to complete this work, to Prof. Dr. S. Nolting, Miinster, who aroused my interest in the subject, and to Prof. Dr. P. Frosch, Heidelberg, who generously provided the necessary technical equipment for investigational use. Clinical examinations are impossible without patients and control persons. I would like to thank all the people who took part in this project.