In The Girl with the Dragon Tattoo, the first volume of Swedish writer Stieg Larsson’s trilogy Millennium, a disgraced journalist, Mikael Blomkvist, retires to the remote, fictional island village of Hedeby, three hours north of Stockholm, where an octogenarian industrialist, Henrik Vanger, has invited him to solve the mystery of his great-niece, who disappeared forty years before, aged sixteen. The key to the puzzle would appear to lie in five names and numbers that the girl, Harriet Vanger, wrote in her diary shortly before vanishing without trace:
Since 32 and 30 are local area codes, it seems reasonable to suppose that these are phone numbers, yet the police found no correspondence between names and numbers. Perplexed, Blomkvist copies the list out and pins it up on the wall of the cabin where he is staying. After he has been on the island some months, his sixteen-year-old daughter turns up out of the blu...