The history of drug laws is characterized by great variability across time and cultures. This variability is particularly evident in the selection of substances for prohibition; drugs that were unregulated for centuries are now widely prohibited, and substances that are now virtually unregulated were subject to strict prohibitions in the past. The aims of drug regulation are also diverse and are often controversial. Whereas proponents of drug regulation typically refer to the protection of the vulnerable and the maintenance of cultural values, critics of drug policy cite institutionalized racism and the indirect pursuit of sociopolitical interests. Indeed, societal efforts to regulate the use and distribution of psy-choactive substances can be traced back to antiquity, and no single attribution captures the confluences of social, political, and ...