This is where the facts of history meet the life of memory. Inside Second Baptist Church, home of Detroit’s oldest black congregation, a polo-shirted tour guide leads a small group of visitors on a journey to the Underground Railroad. She sings a spiritual, "Swing Low, Sweet Chariot," as the tour descends into a cold basement lecture room decorated with historical maps. The story she shares there is as uplifting as the 2,800-pipe organ upstairs. It’s the story of how a city’s residents, some of them from this church, collaborated across the color line to shelter fugitive slaves and get them to freedom in Canada. Fugitives who had been enslaved someplace else.

And the story is true. But there’s another story about slavery in Detroit. Chasing it has become a chief pursuit of one of the visitors touring Second Baptist this Wednesday morning. Tiya Miles is a University of Michigan historian with glasses, long locks, and a voice so quiet it sometimes verges on inaudible. Her demeanor can be misleading. The MacArthur "genius" grant winner and part-time novelist has made a career of doggedly challenging America’s slavery amnesia. "A gentle hammer," one friend calls her.

In her best-known book, Ties That Bind (University of California Press, 2005), Miles followed the trajectory of one black and Indian family to examine the often tragic relationship between two groups whose land and labor built the United States. She told the story of how the Cherokee Indians came to possess 4,000 black slaves by the eve of the Civil War, a history that haunts contemporary struggles over the citizenship rights of those slaves’ descendants in the Oklahoma tribal nation.

But six years ago, chafing at celebratory narratives like the one in this church, Miles decided to dig deeper into Detroit’s past. She discovered that Detroiters held hundreds of people in bondage between the mid-1700s and the early 1800s. The city’s slave system persisted under three colonial regimes, first the French, then the British, and then, thanks to legal loopholes, the American. It implicated storied families whose wealth financed the University of Michigan and whose names continue to grace the region’s landscape.

That "alternative origin story," told in full for the first time in Miles’s new book, The Dawn of Detroit (The New Press), will be news to many of the city’s residents. "People aren’t going to want to hear and think about the fact that we were a city built in part around slavery," says Roy E. Finkenbine, a historian at the University of Detroit Mercy. ...