Acknowledgments

The authors appreciate the encouragement and support received from Michel Petit, Guy Le Moigne and David Steeds during the preparation of this publication. They wish to thank many colleagues for reviewing the draft and offering constructive comments, among them Ashok Subramanian, Shaki Barghouti, John Merriam, Ken Craig, Peter Lee, Jean Goussard, Pierre Rosset, Darell Zimbelmann and many others. Cecilia Gorriz edited the paper and organized the printing.

The support and assistance received is deeply appreciated; the sole responsibility for the content of the paper, however, rests with the authors.