Of all the Founding Fathers, Thomas Jefferson has fared the worst at the hands of revisionists. If he has managed to keep his place on Mount Rushmore, he has been vilified almost everywhere else in recent years as a slave-owning hypocrite and racist; a political extremist; an apologist for the vicious, botched French Revolution; and in general, somewhat less the genius remembered in our folklore than a provincial intellectual and tinkerer.
The onslaught is unfair. But even ardent Jeffersonians admit that the man was an insoluble puzzle. The contradictions in his character and his ideas could be breathtaking. That the author...