This book was written during a year's stay at the Center for Advanced Study in the Behavioral Sciences. Countless authors have sung its praises. Aside from splendid surroundings, unlimited library and secretarial assistance, and a ready supply of varied scholars to consult at a moment's notice, what the center offers is to leave the scholar to his own devices, for good or ill. Would that all men had such wisdom. The final version was consummated with the aid of a grant from the Social Sciences Grants Subcommittee of the Faculty of Graduate Studies and Research of McGill University.