The author is indebted to the Alfred P. Sloan Foundation and to the Graduate School of the University of Minnesota for financial aid. This permitted visits with quite a few old Cowlespeople, reproduction of documents, and some reduction in teaching commitments. The many who responded with information and suggestions cannot be blamed for the shortcomings of the book. Faculty and staff at the Cowles Foundation were particularly helpful. Dori Clifton, Business Manager, and Karlee Gifford, Librarian, were always resourceful in locating people and documents. Michael Intrilgator, Leonid Hurwicz, and Martin Beckmann fur- Intriligator also nished perceptive comments on an earlier draft. obtained my access to the Marschak archives at UCLA. Wendy Williamson, the librarian at the Jacob C. Schmookler Library at the University of Minnesota cheerfully and efficiently handled lots of (sometimes vague) requests for reference materials and produced neat and timely drafts from very trying scratchpaper. Appropriate parts of my correspondence and some copies of documents will be placed in a Cowles Commission archive at the Cowles Foundation, Vale University.