Worst of all, the exodus could no longer be blamed on scattered outbreaks of Drapetomania. Rather, an organized network, vast and sinister, actively encouraged and abetted it. And increasingly, this movement operated not under cover of darkness but in broad daylight.

For most people today—as for most Americans in the 1840s and 1850s—the phrase Underground Railroad conjures images of trapdoors, flickering lanterns, and moonlit pathways through the woods. The century and a half since its heyday has only deepened the mystery. For a saga that looms so large in the national memory, it has received surprisingly little attention from scholars, at least until recently. What’s more, the existing literature sometimes seems to obscure the real story still further. Was the Underground Railroad truly a nationwide conspiracy with “conductors,” “agents,” and “depots,” or did popular imagination simply construct this figment out of a series of ad hoc, un­connected escapes? Were its principal heroes brave Southern blacks, or sympathetic Northern whites? The answers depend on which historians you believe.

Even the participants’ testimonies often contra­dict one another. A generation after the Civil War, one historian (white) interviewed surviving abolitionists (most of them white) and described a “great and intricate network” of agents, 3,211 of whom he identified by name (nearly all of them white). African Americans told a different story. “I escaped without the aid … of any human being,” the activist minister James W. C. Pennington wrote in 1855. “Like a man, I have emancipated myself.”

Now Eric Foner, one of the nation’s most admired practitioners of history—his previous book, on Abraham Lincoln and slavery, won a Pulitzer Prize—joins an increasing number of scholars shining lanterns into the darkness. Several years ago, an undergraduate in Foner’s department at Columbia, at work on her senior thesis, discovered the previously overlooked journal of a white New Yorker who aided hundreds of escaping slaves in the 1850s—a find that inspired his latest book. (The student, he takes pains to mention in his acknowledgments, decided to become a lawyer, so no scholarly careers were harmed in the production of this volume.)

Gateway to Freedom: The Hidden History of the Underground Railroad tells a story that will surprise most readers. Among its biggest surprises is that, despite the book’s subtitle, the Underground Railroad often was not hidden at all. Abolitionist groups made little secret of assisting runaways—in fact, they trumpeted it in pamphlets, periodicals, and annual reports. In 1850, the year of the notorious Fugitive Slave Act, the New York State Vigilance Committee publicly proclaimed its mission to “receive, with open arms, the panting fugitive.” A former slave in Syracuse, Jermain W. Loguen, announced himself in the local press as the city’s “agent and keeper of the Underground Railroad Depot” and held “donation parties” to raise money, while newspapers published statistics on the number of fugitives he helped.