Sexual assault constitutes both physical and mental violence, and it is not easily recovered from. Victims/survivors of sexual assault may experience severe feelings of anxiety, stress, or fear. This book demonstrates some mental health problems that sexual assault victims may experience. It focuses on some topics about (a) post-traumatic stress disorder; (b) obsessive-compulsive disorder; and (c) mental contamination. Clinical experience and empirical studies show that many victims of sexual assault suffer from a distressing feeling of being contaminated for years or decades after experiencing sexual violence. This phenomenon is called mental contamination and was first identified by Rachman (1994). Mental contamination is defined as the experience of contamination-related feelings of dirtiness in the absence of direct physical contact with a contaminant. This psychological sense of contamination involves internal and emotional feelings of dirtiness that may be evoked by unwanted thoughts and images, as well as by memories of negative events such as from sexual assaults. Mental contamination has also been found to be prominent in victims of sexual assault and in patients with post–traumatic stress disorder (PTSD). As behavioral consequences of the feeling of mental contamination, victims of sexual assault suffer feelings of mental contamination and might show excessive washing behavior, and may develop Obsessive-Compulsive Disorder (OCD). The book presents cognitive theory of the mental contamination in order to demonstrate how this problem can be treated. In addition, the book presents clinical guidelines based cognitive behavioural therapy for the mental contamination that can develop.