Marijuana (MAH-rih-WAH-nah) is an informal Mexican term for the dried leaves of the hemp plant (Cannabis sativa), often smoked for its mildly intoxicating effect. After alcohol and tobacco, marijuana is the most popular recreational drug in the United States, often associated with the counterculture of the 1960s. It is reportedly still smoked by an estimated three million Americans every day. Unlike alcohol and tobacco, however, its growth, possession, and use are illegal, although there is a growing interest in making it available for medical use. Marijuana has been reported to be effective in easing the discomfort of patients suffering from glaucoma (a disease of the eye that creates pressure within the eye and can result in blindness) or from terminal illnesses such as AIDS (see entry under 1980s—The Way We Lived in volume 5) or cancer.

The hemp plant has been widely cultivated in the United States since...