Encouraged by the results with radiation genetics, the editors of this volume have tried since 1963 to organize a team of scientists in Heidelberg who would examine the problem of chemical mutagenesis in mammals with a variety of methods. Meanwhile, other organizations have also become interested in this problem and various teams, particularly in the U.S.A., but also in West Germany, are working in this field. This development is very auspicious; the spectrum of our methods does permit limited conclusions as to the mutagenic effects of chemical substances in mammals, but we are still far away from a thorough determination of all the genetically relevant effects. New methods must be developed. This volume is the result of a request by the Chairman of the "Gesellschaft fUr Anthropologie und Humangenetik", Frau Professor Dr. I. SCHWIDETZKY (Mainz), that one of us (F.V.) organize a symposium concerning mutation research in the framework of its annual meeting on October 7, 1969. The most sensible approach seemed to be one of centering the discussion on the test methods employed in mutagenicity research with mammals.With the aid of the Deutsche Forschungsgemeinschaft and the pharma- ceutical industry it was possible to invite scientists from the U.S.A. We wish to thank Firma Thomae, Biberach, Firma Bayer, Leverkusen, and Firma Boehringer, Mannheim, for their contributions. We wish to thank Dr. HAsso SCHROEDER especially for his efforts on our behalf.
