For six years and nine months Harold Macmillan was Prime Minister of England, the longest term since that of Asquith. The post-Suez years were most important to the economic development of England and Macmillan was uniquely well-prepared in economic theory. Therefore, a study of his leadership is more viable than other premature biographies usually are. Mr. Sampson, an excellent Journalist, has been very fair to his subject. Nevertheless, the subtitle's implied uncertainties are the operative phrase for the book as well as the man. Nothing anything the most enamored biographer can do will ever make Macmillan an exciting personality, but Sampson, a careful analyst, has prepared a brief, clear record of Macmillan's political career, showing the Tory accommodating labor's ascendancy, the dignified relaxation of the last few empire bonds, the old order gent faced with the moral and intellectual poverty of the Profumo scandal with Macmillan leaving shortly afterward, unsullied but overshadowed by it. It's a handy book to have around to check against the memoirs-in-progress coming from Macmillan himself.