Bestseller is a treasure trove for its author ... and his readers

Parents struggling to reveal to their children the rewards of reading have found unexpected help in the form of an illustrated fairy tale that reached the shelves of America's bookshops shortly before Christmas.

Parents struggling to reveal to their children the rewards of reading have found unexpected help in the form of an illustrated fairy tale that reached the shelves of America's bookshops shortly before Christmas.

The story of loyalty, love and heroism in a faraway forest does more than nurture the imagination. It could fill the piggy bank too.

Sales of A Treasure's Trove have been soaring; it made its debut last week at number three on The New York Times children's paperback bestsellers list. This is remarkable, since its novice author, Michael Stadther, could not find a single publisher and eventually was obliged to print, publish and distribute it himself.

While there is no denying the charm of its pages - Stadther says he spent 300 hours drawing each of the illustrations - there is something else about the book that is making it rather special. As the title suggests, it simultaneously invites readers to join a real-life treasure hunt. The prizes are worth a total of $1m (£530,000).

It is a stunt from a seriously eccentric and, indeed, generous mind. In the pages of the book are a series of clues to the whereabouts of a dozen 18ct gold coins the author has hidden in different places all over the United States.

Each coin has the image of one of the creatures featured in the book. On the flip-side there is a telephone number. Ring that number and you will be entitled to a piece of jewellery, each resembling one of those creatures.

And, be aware, these are no novelty jewels with cut glass or plastic. Stadther went to a renowned jewellery-making studio in Connecticut in 2003 and ordered 12 unique creations. Most of the them are of platinum, encrusted with diamonds, rubies, emeralds and sapphires

Stadther, who lives north of New York City, has been bombarded with e-mails from fans. "The kids go right for the puzzle and the treasure," he says. "I thought the treasure was for the parents and the story was for the kids, but the opposite happened.

"I hear from parents they're so happy there's a story the family can read together that's not dumbed down." How hard is the hunt? "It's not rocket science," Stadther says. "It's all in front of you." So far, all 12 tokens remain hidden and readers have until the end of 2007 to find them. After that the hunt will be wound up.

The biggest challenge, the author says, was finding suitable hiding places for the coins. They had to be somewhere safe but somewhere easily accessible. "It's been a long time since you could bury something in this country without being sued by somebody," he says.

"It took a very long time to figure out how to hide something so it wasn't buried, it's not on private property, it's not in a cave, it's not underwater and it's not in a dangerous location where I'll get sued."