The present volume is dedicated to Franco Bassani and collects contributions from collaborators and former students working in solid state theory. It has been prepared on the occasion of the Symposium held at Scuola Normale Superiore in Pisa to celebrate his seventy second birthday. The papers presented here illustrate a wide range of topics in the field of the electronic and optical properties of solids that his scientific achievements have had on the development of this field in Italy and abroad. Most of the contributors have been former students of his: not only has Franco been a master in science, but a master in teaching.