Scott Shane's outstanding work Flee North tells the little-known tale of an unlikely partnership between a man who'd been enslaved and an ardent abolitionist. Thomas Smallwood was born in slavery in Maryland in 1801 and managed to purchase his freedom at the age of thirty. He spent the next decade working as a shoemaker and repairer near the Washington (D.C.) Navy Yard before meeting Charles Torrey (1813-1846), a young white minister. Over the ensuing 18 months, the pair helped organize the escape of some four hundred enslaved men, women, and children.

Enslaved people have been running away from their enslavers since time immemorial, often alone but sometimes with the help of others sympathetic to their plight. What makes Smallwood and Torrey's efforts remarkable was the sheer scope of their plans. They weren't content to simply help one or two people flee captivity, but wanted to ...