In everyday life, we explain and predict human actions through beliefs and intentions. We also assume the existence of persons who act on the basis of reasons. Naturalist philosophers do not accept this concept of 'agent causality': what common sense and sociological explanations called reasons should be interpreted as normal causes of actions. As a matter of fact social sciences increasingly use the causal model of the natural sciences in order to explain human actions. In this volume leading specialists in action theory discuss the question: Is the causal model of the natural sciences sufficient to explain human actions or can we expect an explanatory advantage from the classical concept of agent causality? Contributors: R. Boudon, F. Castellani, A. Corradini, M. De Caro, S. Galvan, G. Keil, E. J. Lowe, U. Meixner, A. Mele, T. O'Connor, J. Quitterer, E. Runggaldier, A. Varzi, H. Weidemann