Countless words have been written about John Wilkes Booth since he shot Abraham Lincoln in Ford’s Theater 150 years ago on Tuesday. But the assassin, amazingly, has not yet received a full-dress biography.

That changes this week with the publication of Terry Alford’s "Fortune’s Fool," which delivers fresh revelations about the darkly magnetic Booth’s early violent tendencies (he tortured cats as a boy), up-and-down stage career, growing political extremism, and grisly final hours.

Alford’s book, published by Oxford University Press, is already being hailed as an important contribution, with the Lincoln scholar Harold Holzer praising it in The Wall Street Journal as "so deeply researched and persuasively argued that it should stand as the standard portrait for years."

That research included nearly 25 years in libraries and archives, but also something more unusual: immersion in the world of the Boothies, as the amateur researchers, buffs and obsessives bent on tracking down every last detail and relic relating to the assassination proudly call themselves.

"They have dug up wonderful material over the years," said Alford, a professor at Northern Virginia Community College. "They aren’t professionals, but they have found lots of things historians have missed."

Boothies — the term, some say, originated as an insult used by Lincoln scholars — have long labored under the suspicion of being apologists for the assassin, or worse. But in recent years, their dogged efforts have received more credit from "Lincoln lovers," as Boothies sometimes jokingly call them in return.

Boothies, Alford said, led him to significant new sources, like a previously unknown statement by one of the assassin’s co-conspirators, found in the attic of someone descended from one of Booth’s lawyers. And then there are more questionable artifacts, like the fragment of the crutch Booth used during his 12 days on the run, which Alford bought from a family near Port Royal, Virginia.

"It’s known as the True Crutch," he said. "The joke was that one touch would turn an admirer of Lincoln into a rabid secessionist."

Lay researchers have long played an outsize role in Lincoln scholarship, especially when it comes to the assassination. The historian Mark E. Neely Jr., writing in 1979, lamented that scholars had largely ignored the topic, leaving the field open to "an avalanche of absurd sensationalizing" and conspiracy theories.

That scholarly reticence has lifted somewhat in recent years as studies of how the Civil War is remembered, exemplified by books like C. Wyatt Evans’ "The Legend of John Wilkes Booth" (2004) and Martha Hodes’ "Mourning Lincoln," published in February, have gained ground in the academy. Still, Holzer summed up the lingering aversion to spending too much time focusing on the assassin.

"Booth is repulsive and a murderer," he said. "This was a man who, with a single act, may have postponed for 100 years the chance of any kind of racial reconciliation."

Into the void have swept the Boothies, a loose network of people who congregate at sites like Tudor Hall, the Booth family home near Bel Air, Md., and the Surratt House Museum in Clinton, Md., the former family home of a convicted co-conspirator. Online, the Boothies gather in places like the Lincoln Discussion Symposium, which has more posts on the assassination than on nearly all other topics combined.

The Surratt house, with its costumed guides, attracts some 10,000 visitors a year, and nearly 150 researchers from around the world attended its annual conference this year, including a few mainstream Lincoln scholars. Its 12-hour bus tour of Booth’s escape route through Maryland and Virginia regularly sells out, as does a similar one sponsored by Smithsonian Associates.

Historians credit Boothies with valuable research on topics like Booth’s weaponry, the flags that hung in Lincoln’s box at Ford’s Theater and even the Pennsylvania oil leases Booth speculated in.

"They are familiar with the most arcane details," said Thomas A. Bogar, a retired professor at Hood College in Frederick, Md., and the author of "Backstage at the Lincoln Assassination," a study of the 46 Ford’s Theater employees who were swept up in the investigation. "It stops short of that magic line between extreme interest and obsession."

Booth research certainly retains a goofy streak. Michael W. Kauffman, an independent researcher and the author of "American Brutus: John Wilkes Booth and the Lincoln Conspiracies" (2004), supplemented deep archival digging with field experiments like burning down a tobacco barn similar to the one in which Booth was finally cornered and fatally shot.

Dave Taylor, creator of the website BoothieBarn.com and, at 27, something of the field’s young rebel, has posted videos of a re-enactment of the assassin’s days on the run in the woods, complete with demonstrations of tooth brushing "using Civil War-era tools."

Taylor, a second-grade teacher in St. Mary’s County in Maryland, said his purpose was educational. "Booth is obviously a villain," he said. "I’m not celebrating this man at all, but trying to get a glimpse into his psyche."

Laurie Verge, director of the Surratt House Museum, said that she was bitten by the Booth bug as a 10-year-old when she was shown the nightshirt that a conspirator reputedly left at her great-grandparents’ house, near the Surratts. She said that the museum had worked hard to overcome a perception of sympathy with Booth’s cause.

Today, the museum presents material relating to the Surratts’ seven slaves. On Wednesday, the anniversary of Lincoln’s death, a mourning wreath will hang on the door.

"Just because you’re interested in the mystery of the assassination doesn’t mean you hate Lincoln," Verge said.

Still, the museum remains neutral on the much-debated question of the guilt or innocence of Mary Surratt, the owner of a boardinghouse in Washington, who was convicted of aiding Booth’s conspiracy. She became the first woman executed by the United States government, to the outrage of many in the South.

"The idea of education is to present both sides of an issue and let people draw their own conclusions," Verge said.

Hodes, a professor at New York University, said there was a risk to focusing on the true-crime minutiae of Booth’s plot.

"The details are fascinating, but they can also be a diversion from the stakes," Hodes said. "Booth was a racist and a white supremacist. I think that gets lost."

Alford’s biography hardly stints on that point, showing how fear of black political equality came to consume Booth. It also knocks down the theory, embraced by some Boothies but few professional scholars, that the assassin had support from the Confederate government’s leaders.

But Alford’s book may not end that argument, let alone the larger one over the meaning of Booth’s act.

Over the past decade, he said, it has become customary to put Lincoln pennies face up on the Booth family grave in Green Mount Cemetery in Baltimore, to lock the assassin in the ground. But other people take those pennies and place them in the alley behind Ford’s Theater, with Lincoln’s face down, to lock the president in the ground.

"That Civil War," Alford said, "is still going on."

Jennifer Schuessler, New York Times

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