September 1987, the Faculty Biology of the Vrije Universiteit, Amsterdam commemorated the fact that Prof. Dr. Wilfried Hans Otto Ernst had been active as a scientist for 25 years. This period of 25 years of scientific research started at the Institut flir Angewandte Botanik (Institute of Applied Botany) of the University of Munster, FRG. In 1965 he completed his Ph. D. thesis, entitled "Untersuchungen der Schwermetallpflanzengesellschaften Mitteleuropas unter Einschluss der Alpen. " He was appointed full Professor at the Department of Ecology of the Vrije Universiteit, Amsterdam in 1973. On the occasion of his 25th anniversary as a scientist, a promise was made, though in covert terms, which we could not redeem at that time. The promise held to offer Prof. Ernst a book, in which his former and present staffmembers, Ph. D. students and colle ages should write a review about their specialism concerning a central theme. Now, at the beginning of 1990 we consider the chapters of "Ecological Responses to Environmental Stresses" to be completed. The book reflects the wide range of research approaches that has been initiated and organized by Wilfried Ernst. The editors hope to have attained the primary aim of the production of the book of friends, that is to gather relevant papers of staff-members and colleagues of Wilfried Ernst. The title of the book "Ecological Responses to Environmental Stresses" covers the majority of the chapters included.
