Thomas Jefferson is often portrayed as a hopelessly enigmatic figure--a riddle--a man so riven with contradictions that he is almost impossible to know. Lauded as the most articulate voice of American freedom and equality, even as he held people--including his own family--in bondage, Jefferson is variably described as a hypocrite, an atheist, or a simple-minded proponent of limited government who expected all Americans to be farmers forever. Now,...