The appointment of Earl Warren as Chief Justice of the United States in 1953 marked the opening of a new era in the nation's constitutional development. In these lectures, originally given in somewhat shorter form in Honolulu in the summer of 1967 under the joint auspices of Harvard Law School and the University of Hawaii, Archibald Cox describes the main lines of constitutional development under the Warren Court. He analyzes the underlying pressures involved and the long-range institutional consequences in terms of the distribution of governmental power.