The photograph, scratched and undated, is captioned “Brother Jordan Anderson.” He is a middle-aged black man with a long beard and a righteous stare, as if he were a preacher locking eyes with a sinner, or a judge about to dispatch a thief to the gallows.

Anderson was a former slave who was freed from a Tennessee plantation by Union troops in 1864 and spent his remaining 40 years in Ohio. He lived quietly and likely would have been forgotten, if not for a remarkable letter to his former master published in a Cincinnati newspaper shortly after the Civil War.

Treasured as a social document, praised as a masterpiece of satire, Anderson’s letter has been anthologized and published all over the world. Historians teach it, and the letter turns up occasionally on a blog or on Facebook. Humorist Andy Borowitz read the letter recently and called it, in an email to The Associated Press, “something Twain would have been proud to have written.”

Addressed to one Col. Patrick Henry Anderson, who apparently wanted Jordan to come back to the plantation east of Nashville, the letter begins cheerfully, with the former slave expressing relief that “you had not forgotten Jordon” (there are various spellings of the name) and were “promising to do better for me than anybody else can.” But, he adds, “I have often felt uneasy about you.”

He informs the colonel that he’s now making a respectable wage in Dayton, Ohio, and that his children are going to school. He tallies the monetary value of his services while on Anderson’s plantation — $11,608 — then adds, “we have concluded to test your sincerity by asking you to send us our wages for the time we served you.”

Turning serious, he alludes to violence committed against women back in Tennessee and wonders what would happen to his own family members. “I would rather stay here and starve — and die, if it come to that — than have my girls brought to shame by the violence and wickedness of their young masters.”

He asks if there are schools now for blacks. “The great desire of my life now is to give my children an education, and have them form virtuous habits,” he writes.

Then he signs off with a swift, unforgettable kick.

“Say howdy to George Carter,” he says, “and thank him for taking the pistol from you when you were shooting at me.”

Anderson’s words, a timeless kiss-off to a hated boss, are also a puzzle: How could an illiterate man, newly released from bondage, produce such a work of sophisticated satire?

After the letter resurfaced online earlier this year, along with questions about its authenticity, The Associated Press sought answers.

From documents compiled by the AP and in interviews with scholars, Anderson emerges as a very real person and the very real author of his story — though, from the beginning, it was reported to have been “dictated.” His letter is an outstanding, but not unique, testament to the ability of slaves to turn horror into humor.

“The sly irony is very much in the Mark Twain style,” Twain biographer Ron Powers says of the letter, especially the request for unpaid wages. “Whammo.”

“It is that wonderful combination of serious thought and satirical chastisement,” says Yale University history professor David Blight, who loves to read the letter during a lecture class on Reconstruction. “It represents so many definitions of freedom — dignity, access to education, family. And in the end, it also meant wages.”

According to available records, Jordan Anderson was born somewhere in Tennessee around 1825 and by age 7 or 8 had been sold to a plantation owned by Gen. Paulding Anderson in Big Spring, Tenn. Patrick Henry Anderson was one of the general’s sons; by the mid-1840s he owned Jordan and other slaves. Jordan Anderson married Amanda McGregor in 1848 and they apparently had 11 children.

Union troops camped on the plantation, and Jordan was freed in 1864 by the Provost-Marshall-General of the Department of Nashville.

Roy E. Finkenbine, a professor at the University of Detroit-Mercy who is planning a biography of Anderson, thinks it’s likely Jordan was given to Patrick (born in 1823) as a playmate and personal servant when they were young. According to the 1860 slave schedules in the U.S. Census, Patrick had five “slave houses” totaling 32 people — 19 males and 13 females.

While the schedules don’t list the slaves by name, there were two men, aged 34 and 35, who would have been about the age Jordan was in 1860. Finkenbine says Jordan appears to have been the oldest male slave of working age, and that might be why the plantation owner was so eager to entice him back. Many of the slaves had fled, and Col. Anderson was mortgaged to the hilt.

“Harvest is coming on. Jordan’s a guy who’s played … sort of a quasi-managerial role in the past,” Finkenbine says. “And if he can convince this guy to come back, here’s a guy who can not only maybe get the harvest in, but convince some of these other slaves … to come back and be workers on the plantation. It’s kind of his last-ditch effort to save it.”

But he doesn’t save it. In September 1865, Finkenbine says, Anderson sold the nearly 1,000-acre estate to his attorney for a pittance, in an apparent attempt to get out from under his crushing debt. Just two years later, Patrick Henry Anderson died at the age of 44.

That’s what’s known of the famous letter’s recipient. What of its writer?

Jordan Anderson’s collaborator — to whom he reportedly dictated the letter — was a Dayton banker named Valentine Winters. An abolitionist who once hosted Abraham Lincoln at his mansion, Winters regarded the letter as excellent propaganda, according to Finkenbine. It was originally published in August 1865 by the Cincinnati Commercial, a paper with Republican leanings.

Jordan Anderson likely made his way to Dayton with the help of Winters’ son-in-law, Dr. Clarke McDermont, a surgeon at a Nashville hospital where both Jordan and his wife, Mandy, worked for a time, says Finkenbine, who places Jordan and his family in Dayton by August 1864. Anderson becomes an employee and tenant of Winters.

If Anderson’s letter rings true, it might be because it comes right out of the life he had survived. From the insanity of slavery, he and others developed a deadpan, absurdist take that revealed their feelings to each other and hid them from their masters.

“Slaves had to be guarded as to what they said because they would be punished if caught critiquing or offending the master class — thus they developed sophisticated forms of indirection and other forms of masking,” says Glenda Carpio, a professor of African-American studies at Harvard University and author of “Laughing Fit to Kill: Black Humor in the Fictions of Slavery.”

Anderson’s letter is special in part, Carpio says, because it was written down. Until late in the 19th century, when Joel Chandler Harris’ Br’er Rabbit tales were first published, slave humor was essentially an oral tradition. And while newspapers sometimes printed letters to former masters, Finkenbine notes, few were “so challenging” as Anderson’s.Regarding questions about whether the letter was really Anderson’s, Finkenbine says: “It’s kind of a racist assumption … that when someone is illiterate, we make the assumption they’re stupid.” Enslaved people had deep folk wisdom and a rich oral culture, he adds. “Why would we think that he hadn’t been thinking about these things and couldn’t dictate them to willing abolitionists?”

“I think the letter is clearly his ideas and, for the most part, his own words” — though Winters probably had “some minor role in shaping the language.”