This work was originated during my two-year stay at the economics department of Stanford University in the academic years 1984–6 and my visit to CORE, Belgium, in September 1985. Since then I have had the opportunity (and often the pleasure) of discussing the contents of this research monograph with a number of individuals. I benefited not only from insightful comments made by some scholars, but also from the dogmatic thinking of others, which forced me to be more precise and explicit in my writing. I thank members of both groups.

Special thanks are due to Geir Asheim, Giacomo Bonanno, Edi Kami, Amnon Rapoport, Howard Rosenthal, and Zvi Winer for their very useful and thoughtful comments.

One person, to whom I owe the most for (almost) always being willing to listen, read, discuss, and criticize my ideas, is my friend and colleague Benyamin Shitovitz. His many suggestions concerning both contents and exposition have been extremely helpful.

I have also profited from teaching parts of this book at the following institutions: Haifa University, Israel; California Institute of Technology; G.R.E.Q.E., Marseilles; GSIA, Carnegie Mellon University; University of California at Davis; and the University of Notre Dame de la Paix, Namur, Belgium, where I held the Chaire Francqui Internationale, 1987.