This book, as the title suggests, sets out to provide an overview of two major areas of ‘risky behaviour’ in relation to young people. The first of these relates to the use and misuse of legal and illicit drugs. The second relates to sexual behaviour. It is emphasized that, while risk-taking amongst adolescents is quite normal, most young people do not expose themselves to major risks. The great majority of those who drink do so in moderation. Most young people in Britain, and in several other countries, do not smoke tobacco or use illicit drugs. In addition, growing awareness of the spreading AIDS epidemic has certainly exerted an influence, though often only a marginal one, on the sexual behaviour of adolescents and young adults. This book sets out to put ‘risk-taking’ into a balanced perspective. This necessitates the presentation of a general account of recent evidence related to both the use and the misuse of alcohol, tobacco and illicit drugs and of research evidence related to sexual behaviour and to various forms of risk-taking.