This book is the cuhnination of many years' research inspired by the pioneering and seminal works of Sah and Stiglitz. We gratefully acknowledge the influence of these two authors, whose ideas and contributions have brought us together on this collabo ration, despite our divergent scientific backgrounds (while Catalani is interested in quantitative methods, Clerico is a non-quantitative economist) . We thank the Editor of the Rivista Internazionale di Scienze Economiche e Commerciali for permission to use slightly modified versions of papers published in that Review (they are the content of...