Oxford, England ? It started with a darkly comic image in novelist Mark Haddon’s mind: a dead dog pinned to the ground by a gardening fork.

From that stabbed canine, which Haddon admits some don’t find funny, he created an unlikely murder mystery with an even less likely hero — an autistic teenager whose determination to crack the case leads him to painful discoveries about his own life.

“The Curious Incident of the Dog in the Night-Time” has been on British best-seller lists for months, is a hit in the United States and has received raves from reviewers and those affected by autism. It recently won the Whitbread Prize, one of Britain’s top literary awards.

Haddon had worried that readers would have trouble connecting with Christopher Boone, who as the tale’s narrator describes events in a “just the facts” style that springs from his trouble understanding other people and their emotions.

“I find people confusing,” Christopher tells readers, explaining that he has difficulty decoding facial expressions, jokes and commonly used figures of speech.

He’s far more comfortable with numbers and concrete details and sees fiction as little more than lies. Facts are his friends — like his observation that a teacher’s brown shoes “have approximately 60 tiny circular holes in each of them.”

The novel, presented as a true story that a school counselor encourages Christopher to recount, is peppered with drawings, diagrams and even mathematical formulas. When he rides the London subway, he provides a picture of the pattern on the train’s seats, and he gives his chapters successive primary numbers.

Christopher has Asperger’s syndrome, a mild form of autism in which sufferers have normal intelligence but serious problems relating to others.

Haddon, 41, says he was initially wary of a character he thought might put off some readers but soon realized Christopher’s literalism and logic might make for a compelling viewpoint.

“Here is a character who says he can only tell the truth … who always gets it wrong by getting it right,” the author says. “Here is a narrator who doesn’t understand emotion, and yet the reading experience is for most people quite emotional.”

“He is someone whose mind would be a complete, closed book if you ever met them and yet part of the magic of a novel is that you slip inside their head straightaway,” Haddon says, bouncing his newborn son, Zack, on his lap in the sunny living room of his modest row home near Oxford University.

A humanizing portrayal

The cramped house, where the writer and his wife, Sos, live with Zack and older son Alfie, 3, is littered with books, plastic toys and baby paraphernalia. Haddon squeezes in writing around trips to the day care center.

Haddon did little research on Asperger’s syndrome for the book, relying instead on knowledge gained when he once worked with the physically and mentally disabled.

“The route to understanding someone else is not getting big books out of the library; it’s just using your imagination to put yourself in their shoes, and I think this book helps people do that,” he said.

Those affected by the condition say his approach was a success. They have embraced “Curious Incident” as a humanizing portrayal that gives readers real insight into the thought processes of people with Asperger’s.

“I think it’s very important that he is portrayed first of all as a young man and secondly as a young man with Asperger’s syndrome,” says Carol Povey, of the National Autistic Society. “He comes across as a full person with all sorts of sides to his character.”

Haddon, a broad-shouldered man with close-cropped brown hair and an easy laugh, thinks the sparse style in which he presents Christopher’s voice lets readers interpret events and form their own opinions about other characters, making the story more emotionally engaging.

Convincing and acclaimed

Reviewers agree, and they have heaped praise on the book. The New York Times said it had “a visceral, stripped-down power” and read like a mixture of William Faulkner’s “The Sound and the Fury,” J.D. Salinger’s “The Catcher in the Rye” and the stories of Raymond Carver and neurologist Oliver Sacks.

Christopher, who lives with his father in a small western English town, stumbles upon the murdered dog, named Wellington, in the book’s opening scene and decides to make it the center of the story his counselor wants him to write.

“Siobhan said that the book should begin with something to grab people’s attention,” he says. “That is why I started with the dog. I also started with the dog because it happened to me, and I find it hard to imagine things which did not happen to me.”

As Christopher questions neighbors about Wellington’s death, readers get a peek into his rigidly organized life — he avoids anything brown or yellow, keeps foods separate from one another on his plate and doesn’t like being touched, even by his father. Anything unfamiliar makes him anxious, and he does multiplication to calm himself.

“He seems quite peculiar … but he’s like most people in that he has these habits and patterns which make him feel secure — which everyone does to some extent, (although) they’re not as explicit or as extreme as his,” Haddon said.

Christopher’s inquiries lead him toward a set of painful family secrets that upend his carefully calibrated life. He spends the latter part of the story trying desperately to regain his footing.

Haddon, a children’s book writer who had written five unpublished novels before he sold “Curious Incident,” says he wrote the book for adults. His publisher, Random House has also put out a children’s edition in Britain — Haddon thinks teens could read it.

Many have praised Haddon’s skill in creating a strong, convincing voice for Christopher, and Dan Franklin, a Random House publishing director who was the first at the company to read “Curious Incident,” said that was what captured him. “It’s totally convincing,” Franklin said.

His judgment proved prescient. The book has been on British best-seller lists for months and has sold more than 190,000 copies in the United States, a strong performance.