The papers gathered in this volume were presented at the medical sessions of the First Conference on Mathematics at the Service of Man held in Barcelona, Spain, July 11-16, 1977. Papers presented at the medical sessions were more numerous than those pre sented in any other single area of specialization covered in the conference. Because pf this, the Publications Committee resolved that papers presented at medical sessions be published separately from the proceedings of the conference. The proceedings of the conference have been published by the Esco1a Tecnica Superior d'Arquitectura de 1a Universitat Po1itecnica of Barcelona. The papers contained in this volume were selected on the basis of current interest and willingness of the authors to publish. They are organized not accord ing to the sequence in which they were presented at the conference, but, to the extent that this was possible, in topic areas. As its name indicates, the principal purpose of the conference was to under score the fact that mathematics is a science whose applications are relevant to many aspects of human activity. In the opinion of the editors of this volume, the conference met its objective with success, both in terms of the broad variety of topics covered as well as by the number of nations that were represented at the conference in spite of the special circumstances prevailing in Spain at that time.