THE SAGE OF MONTICELLO by Dumas Malone Little, Brown; 551 pages; $19.95
Old age is an optimist's severest test of character. Thomas Jefferson, who made the "pursuit of happiness" part of the American way of life, kept the faith until he died, 50 years to the day after the Declaration of Independence.
Jefferson was nearly 66 when he stepped down from the presidencythe point at which Dumas Malone begins this sixth and final volume of his awesomely thorough biography, Jefferson and His Time. But he remained a man of uncommon vigor.