This book is the fruit of a study group on perception and action that worked at the Center for Interdisciplinary Research (ZiP) of the University of Bielefeld, FRG in the academic year 1984-1985. We express our gratitude to the ZiF for hosting the group and for providing fmancial and organizational support for its scientific activities, including a meeting of the authors of the present volume that took place at the ZiF in July 1986. This is/ the study group's last common product, and it to...