Watergate has ""dramatized the manner in which a President's system of management not only shapes events but entraps their participants."" In his study of the managerial styles of the last six presidents, Johnson perceives three basic approaches: the ""formalistic"" -- emphasizing hierarchic funneling of information and decision and ""reasoned discussion of prepared briefs""; the ""competitive"" -- delegating overlapping authority in the hope that the consequent clash among subordinates will generate viable policy; and the ""collegial"" -- involving the collective hashing out of problems among the President and his staff. Johnson examines each President in the light of these concepts: Roosevelt's ""competitive approach""; Truman's ""assertive leadership. . . contain[ing] strong undercurrents of permissiveness and dependency""; Eisenhower's ""organized absenteeism""; Kennedy's ""teamwork""; Johnson's ""reign of personality""; and Nixon's ""ordered utopia."" The author traces the roots of the managerial style of each president in his childhood and early career; he minces in the formidable terrain of psychohistory, a landscape requiting more navigational skill and greater sure-footedness than he has. Apart from this flaw, Johnson's investigation is assiduous and comprehensive, a valuable dissipation of the fog enveloping presidential performance. Most timely.