"All drugs are dangerous substances," the author writes, "because they open new dimensions of seeing, thinking, feeling and being." Klein, a medical anthropologist, goes on to conduct a forensic denunciation of contemporary drug prohibition as counterproductive and based on historically contingent assumptions. Rehearsing the history of drug scares in Europe, he explains the Byzantine contemporary international structures of the drug-control bodies, and the irrational separation between alcohol and nicotine on the one hand, and the rest of the pharmacopeia on the other.

The war on drugs is also devastating to developing economies, as he shows with reference to South America, the Caribbean and the southern Caucasus. Meanwhile, in the US, drug penalties carry effectively racist weightings - crack cocaine, largely used by African-Americans, attracts 100 times greater jail time per gram than cocaine powder, mostly snorted by whites. The problem is systemic: "Many of the key professionals have a stake in maintaining a system that can only disguise its failings by continuously expanding its activities." I was left glad that tea happens to be legal.