Even as a child, Tom Hayes was obsessed with numbers. He loved their simplicity, their objectivity. Equations were beautiful.

By his teenage years, that affinity had translated into a love of gambling. Hayes grew to hate that term; to him, it suggested his winning wagers were the product of luck, not skill. He relished hunting for and exploiting weaknesses in everything from slot machines in English pubs to rival traders at the world's biggest banks. He had a hearty appetite for risk, as long as he felt that he understood the odds.