The country has widely discussed the so-called "management of news." The controversy over William Manchester's Death of a President, together with lesser contretemps over earlier books, about President Kennedy and his Administration, suggests a companion subject: the management of history. When do contemporary affairs become history? What are the responsibilities and obligations of those who propose to write that history and of those who help to make it? One man's view is conveyed in this elaboration of an address to the American Historical Association. Mr. Schlesinger writes both as a historian (The Age of Jackson, The Age of Roosevelt) and as a participant in many of the events recorded in his widely read A Thousand Days, a chronicle of John Kennedy's presidency.