Stories of the Underground Railroad provide the possibility of moral comfort in a profoundly uncomfortable past. Illustration by Leigh Guldig

The crate arrived, via overland express, one spring evening in 1849. Three feet long, two feet wide, and two and a half feet deep, it had been packed the previous morning in Richmond, Virginia, then carried by horse cart to the local office of the Adams Express Company. From there, it was taken to the railroad depot, loaded onto a train, and, on reaching the Potomac, transferred to a steamer, where, despite its label—THIS SIDE UP WITH CARE—it was placed upside down until a tired passenger tipped it over and used it as a seat. After arriving in the nation’s capital, it was loaded onto a wagon, dumped out at the train station, loaded onto a luggage car, sent on to Philadelphia, unloaded onto another wagon, and, finally, delivered to 31 North Fifth Street. The person to whom the box had been shipped, James Miller McKim, was waiting there to receive it. When he opened it, out scrambled a man named Henry Brown: five feet eight inches tall, two hundred pounds, and, as far as anyone knows, the first person in United States history to liberate himself from slavery by, as he later wrote, “getting myself conveyed as dry goods to a free state.”

McKim, a white abolitionist with the Pennsylvania Anti-Slavery Society, had by then been working for the Underground Railroad for more than a decade, and he was awed by the courage and drama of Brown’s escape, and of others like it. In an article he wrote some years later, he predicted that future generations of Americans would come to share his emotions:

Now deemed unworthy of the notice of any, save fanatical abolitionists, these acts of sublime heroism, of lofty self-sacrifice, of patient martyrdom, these beautiful Providences, these hair-breadth escapes and terrible dangers, will yet become the themes of the popular literature of this nation, and will excite the admiration, the reverence and the indignation of the generations yet to come.

It did not take long for McKim’s prediction to come true. The Underground Railroad entered our collective imagination in the eighteen-forties, and it has since been a mainstay of both national history and local lore. But in the past decade or so it has surged into “the popular literature of this nation”—and the popular everything else, too. This year alone has seen the publication of two major Railroad novels, including Oprah’s first book-club selection in more than a year, Colson Whitehead’s “The Underground Railroad” (Doubleday). On TV, the WGN America network aired the first season of “Underground,” which follows the fates of a group of slaves, known as the Macon Seven, who flee a Georgia plantation.

Nonfiction writers, too, have lately returned to the subject. In 2004, the Yale historian David Blight edited “Passages to Freedom,” an anthology of essays on the Underground Railroad. The following year, Fergus Bordewich published “Bound for Canaan,” the first national history of the Railroad in more than a century. And last year, Eric Foner, a historian at Columbia, published “Gateway to Freedom,” about the Railroad’s operations in New York City. Between 1869 and 2002, there were two adult biographies of Harriet Tubman, the Railroad’s most famous “conductor”; more than four times as many have been published since then, together with a growing number of books about her for children and young adults—five in the nineteen-seventies, six in the nineteen-eighties, twenty-one in the nineteen-nineties, and more than thirty since the turn of this century. An HBO bio-pic about Tubman is in development, and earlier this year the U.S. Treasury announced that, beginning in the next decade, she will appear on the twenty-dollar bill.

Other public and private entities have likewise taken up the cause. Since 1998, the National Park Service has been working to create a Network to Freedom, a system of federally designated, locally managed Underground Railroad sites around the country. The first national museum dedicated to the subject, the National Underground Railroad Freedom Center, opened in Cincinnati in 2004, and next March the Park Service will inaugurate its first Railroad-related national monument: the Harriet Tubman Underground Railroad State Park, in Cambridge, Maryland, near Tubman’s birthplace.

This outpouring of interest suggests that we have collectively caught on to what McKim long ago understood: that the stories of those who fled slavery and those who helped them to freedom are among the most moving in our nation’s history. It was McKim’s hope that these stories would excite our admiration, reverence, and indignation, and they do. But, as more recent work has made clear, they should also incite our curiosity and skepticism: about how the Underground Railroad really worked, why stories about it so consistently work on us, and what they teach us—or spare us from learning—about ourselves and our nation.

No one knows who coined the term. Some ascribe it to a thwarted slave owner, others to a runaway slave. It first appeared in print in an abolitionist newspaper in 1839, at the end of a decade when railways had come to symbolize prosperity and progress, and three thousand miles of actual track had been laid across the nation. Frederick Douglass used the term in his 1845 autobiography—where he laments that indiscreet abolitionists are turning it into “an upperground railroad”—and Harriet Beecher Stowe used it in 1852, in “Uncle Tom’s Cabin,” when one slave-catcher cautions another against delaying pursuit of a fugitive “till the gal’s been carried on the underground line.” By the following year, the Times was reporting that the term had “come into very general use to designate the organized arrangements made in various sections of the country, to aid fugitives from slavery.”

Seldom has our national lexicon acquired a phrase so appealing to the imagination, or so open to misinterpretation. In his new novel, Colson Whitehead exploits both those qualities by doing knowingly what nearly every young child first learning our history does naïvely: taking the term “Underground Railroad” literally. His protagonist, a teen-age girl named Cora, flees the Georgia plantation where she was born into slavery and heads north on a series of rickety subterranean trains—one- or two-car numbers, driven by actual conductors and reached via caves or through trapdoors in buildings owned by sympathetic whites.

Whitehead has a taste for fantastical infrastructure, first revealed via the psychically active elevators in his brilliant début novel, “The Intuitionist.” Those elevators were the perfect device—mingling symbolic resonance with Marvel Comics glee, absolved of improbability by the particularity and force of Whitehead’s imagination. In “The Underground Railroad,” he more or less reverses his earlier trick. Rather than imbue a manufactured box with mystery, he turns our most evocative national metaphor into a mechanical contraption. It is a clever choice, reminding us that a metaphor never got anyone to freedom. Among his other concerns in this book, Whitehead wants to know what does: how the Underground Railroad really worked, and at what cost, and for whom.