A lottery is a process that allocates something of value, such as money or prizes, by chance. It is often used to fill positions in limited resources such as kindergarten admission at a reputable school, housing units in a subsidized building block, a spot in a sports team, or a vaccine against a rapidly spreading disease.

Lotteries are ancient; they were popular in the Roman Empire (Nero was a fan), and are attested to in the Bible, where the casting of lots was used to decide everything from who would be king to who would keep Jesus’s clothes after his Crucifixion. More recently, they have served as a way to raise funds for public works and, in some cases, as an alternative to raising taxes.

The modern lottery, Cohen writes, owes its existence to a confluence of factors: a growing awareness of the potential profits to be made in the gambling business, state budget crises in the late nineteen-twenties that could not be solved without raising taxes or cutting services, and the antipathy among many white voters for paying for services in urban areas they had recently fled.

Those factors have combined to produce eye-popping jackpots that are more common than ever, while the odds of winning a prize remain the same. The result is that people are still buying tickets, even though they know that the chances of winning are slim. To help explain why, Cohen turns to an old trick from economics: the fractal nature of risk.