Walter Dean Myers, newly installed as the National Ambassador for Young People’s Literature, likes to present social problems in his hard-nosed children’s books. But the author, who has sold more than 15 million copies of his more than 100 books, presents a conundrum himself: How does a 74-year-old man keep up with teens not born until he was a fossil?

The Harlem-raised high-school dropout — reared in grinding poverty by foster parents who were barely literate — remembers Sugar Ray Robinson in his flamingo pink Cadillac tooling down Morningside Avenue. He bumped into Joe Louis walking into the Apollo Theater. Langston Hughes used to sell books out of a suitcase at Myers’ church.

And here he is, this grandpa from the World Before Television, writing world-class books for kids too young to have seen Michael Jordan play basketball.

“I don’t really don’t think I do” keep up with them, he says, his voice still rounded on the edges from a childhood speech impediment. “I don’t put that much slang in the stories. The reading level is rather low in most of them. I’m very straightforward, very simple. Kids get the feel of it, and they think it’s good.”

He’s a tall, lanky man, bespectacled, with salt and pepper hair. His life story and career is too farfetched to be anything but nonfiction, but he doesn’t go on about it. You almost have to lean forward to hear him. He lives in Jersey City with his wife of 45 years, Connie. He has two sons, Michael and Christopher, the latter is an artist who illustrates some of his books. A daughter, Karen, died of AIDS three years ago. It’s a brutal thing, still.

Walter Dean Myers has been named new National Ambassador for Young People's Literature, 2012-2013. (Malin Fezehai)

He was in town this month, to be named the nation’s third youth-lit ambassador at the Library of Congress. It’s an unpaid but prestigious post akin to being the poet laureate for the middle-school set. His predecessors are Jon Scieszka, author of merry pratfalls such as “The Stinky Cheese Man and Other Fairly Stupid Tales,” and Katherine Paterson, the grand dame of the genre, best known for “Bridge to Terabithia.”

The Library of Congress’s Center for the Book, the Children’s Book Council and its foundation, Every Child a Reader, sponsor the position. The gig is to heavily promote children’s literacy. Myers, who appeals most directly to young black readers in urban settings, is already a hit.

“We’re already flooded with requests for him,” says John Y. Cole, director for the Center for the Book.

This is no surprise. He’s a three-time finalist for the National Book Award (for Young People’s Literature category), a five-time winner of the Coretta Scott King Award, a two-time Newberry Honor recipient and has a shelf of awards for children’s books.

His métier is neither the world of boy wizards nor that of love-struck teenage vampires. Some of his work is nice picture books, and some of it is poetry, but a lot of the novels might worry parents who see them tucked in their kid’s backpack. “Monster” is about a young man charged with murder. “Dope Sick” is about a kid with a heroin habit. “Autobiography of My Dead Brother” is self-described as being about a neighborhood “plagued by drive-bys, vicious gangs and abusive cops.”

Gaelyn Smith, an eighth-grader at Capitol Hill Day School, came with her class to the ceremony at the Library of Congress. First captivated by “Crystal,” about a teenage model facing difficult choices, she has gone on to devour more than a dozen of his books. “His books are real,” she says. “They’re not contrived at all. There’s no generational barrier. That he’s able to do that is amazing.”

Critics tend to gush. “A vivid and genuine portrait of life that will have a palpable effect on its readers,” said the School Library Journal of “Autobiography.” Publishers Weekly on “Monster”: “A riveting courtroom drama that will leave a powerful, haunting impression on young minds.” The New York Times says, “Myers is a master of observing kids in tough places.”

‘Monster’ by Walter Dean Myers. (Amistad)

The last is no surprise, either. The man writes what he knows.

“I’m like the children I’m trying to reach,” he says.

He was born in Martinsburg, W.Va., during the Great Depression. His biological mother died when he was a toddler. His biological father gave him away to a former wife and her new husband, who lived in Harlem. This father, Herbert Dean, a laborer, was so illiterate that he signed his name with an “X.” Mom, Florence, was Native American and German, drank to excess and worked at a button factory or at home. (He regards them as his “real” parents and added “Myers” to his name out of love and respect.)

He was big and strong, even in elementary school. His speech impediment — he says he still doesn’t know exactly what it is, but says it’s apparently genetic — caused him to hear his own words clearly but to others, it would come out garbled. In his memoir, “Bad Boy,” he recounts a boy mocking his speech in the second grade, chanting “Dabba! Dabba! Dabba!” Myers punched him out. “I liked to fight a lot,” he says.

He was preternaturally bright. What he loved most was his mother reading romance stories to him.

“The sound of Mama’s voice in our sun-drenched Harlem kitchen was like a special kind of music, meant only for me,” he writes. “It was almost a secret language, one that only the two of us understood.”

He was sent to a high school for smart kids, but by his junior and senior years, he was officially designated as troubled. He played basketball on the street, fought, rarely went to class, worked menial jobs for survival cash, fell into depression and never graduated. He joined the U.S. Army at 17. He read voraciously and wrote well but never attended college.

After three years in the Army, he worked in New York as a messenger, a factory worker and as a laborer at a construction site. He said the world around him taught that “there was no advantage in being black.” He thought he’d be “an intellectual” instead, as if that were a race unto itself.

He started writing in 1961 as a means of escaping the lousy world around him. He eventually got a job as an editor in a publishing house. When he was laid off, in 1977, Connie urged him to give full-time writing a shot.

“He’s been writing at home ever since,” she says.

He rises by 5 a.m., writes five pages a day, five days a week, and doesn’t goof around. Last year, at 73, he published five books.

He hopes to accomplish a couple of things in his two years as ambassador. He wants to convince parents to start reading to their children as soon as they’re born and constantly until they’re 5. And he wants to help remove the stigma from teenagers who can’t read well.

“I’ve seen the value of that in my own life.”

He says he often sees this most clearly when he is visiting juvenile detention facilities and prisons. He once had a man tell him that when he was in third grade, Myers came to his class to give a speech and told the children that he was working on a book. These many years later, the third-grader was now an inmate in a maximum security prison. He asked Myers if he’d ever finished it.

At the Library of Congress, and later at Politics and Prose, Myers speaks only for a few minutes. He talks about how his mother, whom he loved, devolved into alcoholism. He says his father never let him know he was unable to read. He mentions how proud his mother sounded when he once overheard her telling neighbors this his job was “typing stories for children.”

The last is a oft-told bit designed to get a wry laugh from its audience, which it does. There is not a trace of bitterness to the tale and not much sadness. It is impossible to know, looking at Myers at the microphone, of his extraordinary losses, of his heartbreaks.

Instead of those things, he talks almost entirely about love, gratitude and the joys afforded him. His words are short, deceptively simple and freighted with meaning. They make you think about a lot of things.

“It’s such a good life,” the man says, softly.