will probably be clarified by the continued cooperative efforts of scientists such as those in the group that met in Berlin last September. The staff of Dahlem Konferenzen is responsible for making the meeting of this group memorably pleasant and pleasantly mem- orable. Dr. Bernhard's gifts of charm, organizational skill, and administrative toughness assured that the conference was run elegantly, smoothly, and decisively, even down to the choice of editors for this volume. Marie Cervantes-Waldmann performed minor miracles extracting manuscripts gently but persistently from the authors and in...