Drugs can be injected, snorted, smoked or swallowed. They can heighten excitement or numb emotion. They are sold by multi-national corporations and on street corners. They can cure and kill. Matters of Substance is a fascinating global tour of drugs and our ambivalent relationship with them. From alcohol to amphetamines, cannabis to crack cocaine, heroin to valium, Griffith Edwards reveals the history, culture and language behind each type of drug - their physical and psychological effects, medical uses, trade routes, the involvement of big business and the chequered path of control and legislation. He considers the key issues surrounding drugs: which are most dangerous? Why do some people become addicted? What causes a drug epidemic? As Edwards argues, only when we truly understand drugs can we hope to deal with them, and this enlightened and informative book will inform all future debates on the subject.