'Stalking' - repeated, unwanted contact or intrusive behaviour from another person which causes fear or distress - affects huge numbers of people. The public perception is that only celebrities are the victims of stalkers, but over the course of their lives twenty per cent of women in Britain will have been stalked. It is often, though, difficult to confirm stalking and to take action against its perpetrators. Stalkers range from the socially inadequate to delusional and psychotic; but they are all singularly and pathologically persistent. Dr Raj Persaud explores the present situation and asks what more can be done. He hears from psychiatrists, psychologists, the police and victims of stalking. Some have been stalked for over 40 years. Raj Persaud also examines how to stop stalkers and prevent them from reoffending.