Joseph Kraft focuses a powerful telescope on the sources of power in Washington, as they have evolved since the Kennedy Administration. The move from systems-thinking to folk-thinking was begun by JFK (""His true metier was to be President of the United States"") and completed by LBJ (""His genius is to be the average writ large""), resulting in a spectacular accretion of power to the Presidency. The old Establishment sealed its doom when it put forward Dean Rusk for Secretary of State. Mr. Kraft concentrates attention on the forces at the Center-- Presidents Kennedy and Johnson, the West Wing, Congress; on the outside insiders--Rand, the military schoolmen, the intellectuals, the Washington lawyers, the press (particularly Scotty Reston); on the bureaucratic machinery --the Pentagon, Budget, J. Edgar Hoover at the FBI, the Never Again Club, Harriman and Acheson (old school), Bundy (logical successor), Rusk (new bureaucratic look). A majority of these pieces have appeared in Harper's Magazine. They form a vigorous, albeit paradoxical assessment.