KIM PEEK bowls into the B&B and, with a slightly sidelong gait, heads straight for the small kitchen, where he tilts his brow quizzically and regards the chef with a beady eye.

Peek’s father, Fran, who has rushed through the hall to catch up with his son, says to the chef: “Give him your birth date.”

“December 12, 1972,” says a bemused John Davis, as Kim crinkles up his eyes behind thick glasses and cracks a gleeful grin. “You were born on a Tuesday, this year it’s a Monday, you will retire in 2037 on a Saturday,” Kim says. He then rattles off the teams, scores and home-run details of the 1972 baseball World Series and, when Davis names his hometown in Oregon, Kim lists all the postcodes, utility-company addresses, roads and TV stations that he has memorised from local directories and atlases. He can repeat this exercise for anywhere in the United States.

Kim’s face is not familiar, but the rapid monotone that delivers this helter-skelter information is instantly recognisable as the style of his famous fictional alter ego, Rain Man. Kim Peek is the real-life autistic savant who inspired Dustin Hoffman’s eponymous character in one of Hollywood’s most memorable films. Peek, 53, is more sociable, more complex and many times more prodigious than the movie character: in subjects from music to history to total recall of the works of Shakespeare. But he needs help cleaning his teeth and getting washed and shaved.

Now Kim’s astonishing brain has sparked a Nasa experiment that could unlock secrets stretching from deepest space travel to the furthest interiors of the human mind.

“It’s going to be really great for me,” intones Kim, as he sits down on a sofa and grasps a glass of water with both hands. At the slightest prompt he launches into a rapid-fire family history of his forebears’ arrival in New England from Norfolk, their subsequent migration to Utah and their involvement with polygamy when it was at its height in the Mormon community in the 1920s.

To break the bombardment of the monologue his son has embarked on, Fran suddenly reaches into a cloth bag, heaves out a familiar-looking gold statuette and puts it on the coffee table. “The Oscar! The Oscaaarrrrrr!” Kim shrieks. He puts his head back and half-giggles, half-roars, then drums his fists on his thighs in childlike excitement.

In addition to Best Movie and Best Actor Oscars, the screenwriter Barry Morrow also won an Oscar for creating the movie. Says Morrow: “He came to visit me after the Academy Awards and was mesmerised by the Oscar.” Morrow has allowed the Peeks to look after the statuette and they take it on speaking tours.

Rain Man’s story of actor Tom Cruise’s selfish yuppie Charlie Babbitt discovering that a brother he never knew existed has been left their father’s fortune, then kidnapping him from an institution and driving him to California in a Buick, bears no resemblance to the Peeks’ life story.

Kim has the staggering arithmetic skills of the Raymond Babbitt character, and can count playing cards. But Kim displays these talents only if he wants to. Morrow recalls, chuckling: “I took him to Reno to see if he could beat the casino. He read and memorised an entire book about gambling, but would not play the tables because he said it was unethical.”

The film in 1988 was a turning point in Kim’s life. He had been a virtual recluse all his life, venturing into the wider world only occasionally, such as to the conference of the Association of Retarded Citizens, where he met Morrow. Hoffman spent a day with Kim and was so awed by his abilities that he urged a reluctant Fran to share his son with the world.

Fran was afraid that Kim would get frightened and upset. Or that he would be regarded as a freak show. But Kim has blossomed into a much more sociable person, and the Peeks have crisscrossed the US and talked to more than two million people.

Kim has read more than 9,000 books and memorised them with his photographic mind.