It follows naturally from the widely accepted Darwinian dictum that failures of populations or of species to adapt and to evolve under changing environments will result in their extinction. Population geneti cists have proclaimed a centerstage role in developing conservation biology theory and applications. However, we must critically reexamine what we know and how we can make rational contributions. We ask: Is genetic variation really important for the persistence of species? Has any species become extinct because it ran out of genetic variation or because of inbreeding depression? Are demographic and environmental stochas ticity by far more important for the fate of a population or species than genetic stochasticity (genetic drift and inbreeding)? Is there more to genetics than being a tool for assessing reproductive units and migration rates? Does conventional wisdom on inbreeding and "magic numbers" or rules of thumb on critical effective population sizes (MVP estimators) reflect any useful guidelines in conservation biology? What messages or guidelines from genetics can we reliably provide to those that work with conservation in practice? Is empirical work on numerous threatened habitats and taxa gathering population genetic information that we can use to test these guidelines? These and other questions were raised in the invitation to a symposium on conservation genetics held in May 1993 in pleasant surroundings at an old manor house in southern Jutland, Denmark."

This volume contains the papers presented at a symposium on popula tion biology sponsored by the Deutsche Forschungsgemeinschaft. It was . held at the guest house of the University of Ttibingen at Oberjoch on May 15-19, 1983. Prior to this conference a small group of European biologists had met in Berlin (June 1981) and Pavia (September 1982) to discuss re search problems on the borderline between population genetics and evolutionary ecology. From the contributions and discussions at these meetings it became evident that the unification of approaches to evolutionary problems in population genetics and evolutionary ecology has not yet been suc cessful and requires further efforts. It was the consensus that a larger symposium with international participation would be helpful to con front and discuss the different approaches to population biology in order to assess "where we are now" and "where we should be going. " As a result an organizational committee was formed (F. Christiansen, S. Jayakar, V. Loeschcke, W. Scharloo, and K. W6hrmann) to iden tify topics that seemed, at least to them, to be fruitful in tackling problems in population biology. Consequently, a number of colleagues were asked to participate in the meeting. We have divided this book into chapters corresponding to the eight topics chosen. The volume begins with the relation between genotype and phenotype and is followed by a chapter on quantitative genetics and selection in natural populations."