The author, a journalist, intended a book that would come somewhere between the recent scholarly studies of Presidential power and the many personal commentaries that President Truman wrote about his administration. The result is a very readable mixture of political history and biography. His story goes from the days of ""Good God, Truman will be President!"" to the Truman family's departure from Washington on Eisenhower's inauguration day. As the subtitle indicates (The History of a Triumphant Succession) the author is warmly admiring of his subject. He describes a man aware of his own ordinariness who never doubted his own worth and who was determined not to allow the powers of the Presidency to atrophy or slip from the control of the Executive Branch. Mr. Phillips traces the events of an exciting administration beset by the problems of establishing peace abroad and prosperity at home, the last involving disgruntled labor and war-restrained businessmen. Anecdote by anecdote, the author brings the Truman days back. Quoting, ""Right in all big things and wrong in all small ones,"" he does not avoid the more embarrassing petty scandals that led to charges of ""That mess in Washington,"" although the overall tone is partisan. Mr. Phillips' achievement is that he has captured on paper the scrappy vigor of Truman, his warmth, and his healthy respect for the office he gained by chance rather than design.