DARTINGTON, England (Reuters) - Solving the world's greatest mathematical riddle sparked suicidal despair, duelling at dawn and women dressed as men before a mild-mannered Englishman finally cracked it.

Andrew Wiles, whose eyes still mist over when he recalls his Eureka moment in 1995, had just pen, paper and pure logic in his lifelong quest to solve Fermat's Last Theorem. The infuriatingly simple riddle posed by the French mathematician baffled the world's finest brains for 350 years.

When Wiles won the big prize and international academic acclaim it was the mathematical equivalent of splitting the atom or finding the structure of DNA. Pure intellect had triumphed at last.

The man who caused centuries of mental agony was Pierre de Fermat, who declared there was no solution to the equation xn + yn - zn where 'n' represents any number greater than two. He then infuriated leading brains for centuries by scribbling beside the equation: "I have found a truly marvellous proof which this margin is too narrow to contain."

Now the tale of Wiles' math detective work has become an unlikely international best-seller by science journalist Simon Singh. "His story is so magical," Singh said, explaining the intricacies of Wiles' solution to a literary festival in western England.

"If you were writing a Hollywood script it's like Indiana Jones discovering buried treasure. This is the greatest scientific story I have ever come across. He has made a true scientific breakthrough of monumental proportions."

Singh's boundless enthusiasm carries readers along even if they have to grapple with the mathematical complexities of the Taniyama-Shimura conjecture, the Kolyvagin-Flach method and of course that notorious old teaser, the Epsilon conjecture. Throw in elliptic curves and modular function and you have a tough job keeping the reader hooked.

But Singh's tale works because of the fascination Fermat inspired in the world's greatest brains over the centuries.

-- French mathematician Sophie Germain took on the identity of a male student to pursue the theorem quest in a field once forbidden to women.

-- Evariste Galois frantically recorded the results of his research deep into the night before going out at dawn to meet his death in a pistol duel over a woman.

-- Japanese genius Yutaka Taniyama, after grappling with the problem, killed himself in despair.

-- German industrialist Paul Wolfskehl, thwarted in love by a woman who spurned him, vowed to kill himself at midnight. He went into his library, picked up a book on Fermat and became so engrossed by the problem that he worked on it until dawn.

Saved by his numbers fascination, he offered a prize to the mathematician who could solve the riddle, and entries poured in from around the world.

Enter Wiles, a shy genius who first read about Fermat at the age of 10 and spent the next 34 years solving the riddle.

"What I admire most about Wiles is that he achieved his childhood ambition and had the guts to follow that dream and make it come true," Singh said.

Wiles worked for years in secret, telling his wife what he was studying only when they were on their honeymoon. He told Singh it was like stumbling around a dark mansion:

"One enters the first room and it is completely dark. One stumbles around bumping into the furniture but gradually you learn where each piece is. Finally, after six months, you find the light, you turn it on and suddenly it is illuminated. ... Then you move into the next room."

When Wiles emerged blinking from this labyrinth of the mind, he became the most famous mathematician in the world. He was front-page news. People Magazine voted him one of the 25 most interesting people of the year, along with Princess Diana and Oprah Winfrey.

An international clothing chain even asked the mild-mannered genius to endorse their new range of menswear.

Then the nightmare returned. One of the referees checking his densely argued 140-page proof found a flaw. It took 14 months of agonising calculation before he finally resolved it.

Now, after his titanic struggle, Wiles confessed to acute withdrawal symptoms mixed with an overwhelming feeling of satisfaction. "Having solved the problem, there is certainly a sense of loss but at the same time there is a tremendous sense of freedom. That is a long time to think about one thing. That particular odyssey is now over. My mind is at rest."