Drug policy sits at the intersection of morality, crime, and public health. Harvard economist Roland Fryer draws on a deeply personal experience to examine what economics reveals about drugs, addiction, and the laws meant to contain them.

Fryer builds on others’ work to argue that even addiction follows economic logic: people respond to incentives. Increasing taxes on cigarettes prompts a certain percentage to quit smoking, and the money made from those who don’t can be spent on additional efforts to curb the behavior. But hard drugs like crack and heroin are outright illegal, and no matter their prices or number of users, all of the proceeds go to dealers and cartels, not harm-reduction programs.

Prohibition, Fryer argues, has made drugs more potent and more dangerous. The harder question is whether legalization, paired with taxation and regulation, might be a more effective tool for reducing harm than criminalization alone.