The misuse of substances has become a notable public health problem over recent years. This medical speciality is conventionally dealt with by psychiatrists, who are being called upon with increasing frequency to give expert opinions on how substance misuse impairs functioning in various areas of the law, including crime, family/child practice and employment. The law has developed its own rules, many of them based on public policy, to deal with parties involved with these situations and in related litigation. The background to understanding the issues in medico-legal situations also includes consideration of social and cultural factors and clinical presentation following misuse. This book deals with all relevant aspects of substance misuse, as it concerns psychiatric practice in relation to medico-legal situations, in a manner which makes the law comprehensible.