In this health-conscious age there is increasing concern about tobacco smoking and inappropriate consumption levels of alcohol. Alcoholism poses an important occupational health problem which can affect an individual's personal welfare and limit his or her efficiency at work. There is concern about the increasing availability of drugs in society, the link between drug-taking and the spread of HIV in society, and the ways in which substance misuse generates more violence within society. Both excessive alcohol consumption and drug-taking may dispose an individual to antisocial actions and lead to criminal activities. By examining the underlying biological and psychological nature of these behaviours the book is intended to inform its readers of current advances in a number of relevant disciplines and to demonstrate some of the problems in collecting and interpreting information from particular groups. 2