Henry Wiencek's eloquent, persuasive Master of the Mountain--based on new information coming from archival research, archaeological work at Monticello, and hitherto overlooked or disregarded evidence in Thomas Jefferson's own papers--opens up a huge, poorly understood dimension of Jefferson's faraway world. We must, Wiencek suggests, follow the money.

Wiencek's Jefferson is a man of business and public affairs who makes a success of his debt-ridden plantation thanks to what he calls the "silent profit" gained from his slaves--and thanks to the skewed morals of the political...