In July 1891 Charles Wells went to the casino at Monte Carlo – the only place in Europe where gambling was legally permitted at the time. He arrived at mid-day and started to gamble at the roulette table. And in the course of eleven hours he broke the bank – not just once but several times in a row. And then, on subsequent days, he did exactly the same again. In less than a week he had won £40,000, worth £4 million in today’s terms.

Even now, 125 years later, no-one is quite sure how he achieved this seemingly-impossible feat. Some claim that, as an engineer, he could have discovered a slight mechanical imperfection in one of the roulette wheels, enabling him to predict which numbers to bet on. Other observers speculate that, as a fraudster, he had probably devised a way to swindle the casino. Wells himself dismissed these accusations, claiming that he had invented an infallible system of gambling which involved watching for recurring sequences of numbers before placing his bets. To me, though, none of these explanations seemed convincing, and I set out to solve the mystery.

My book, *The Man who Broke the Bank at Monte Carlo, *is a biography of Charles Wells, and contains my own analysis of his extraordinary bank-breaking achievements!