Parental alienation is an important phenomenon that mental health professionals should know about and thoroughly understand, especially those who work with children, adolescents, divorced adults, and adults whose parents divorced when they were children. In this book, the authors define parental alienation as a mental condition in which a child - usually one whose parents are engaged in a high-conflict divorce - allies himself or herself strongly with one parent (the preferred parent) and rejects a relationship with the other parent (the alienated parent) without legitimate justification. This process leads to a tragic outcome when the child and the alienated parent, who previously had a loving and mutually satisfying relationship, lose the nurture and joy of that relationship for many years and perhaps for their lifetimes. We estimate that 1 percent of children and adolescents in the U.S. experience parental alienation. When the phenomenon is properly recognized, this condition is preventable and treatable in many instances. The authors of this book believe that parental alienation is not simply a minor aberration in the life of a family, but a serious mental condition. Because of the false belief that the alienated parent is a dangerous or unworthy person, the child loses one of the most important relationships in his or her life. This book contains much information about the validity, reliability, and prevalence of parental alienation. It also includes a comprehensive international bibliography regarding parental alienation with more than 600 citations. In order to bring life to the definitions and the technical writing, several short clinical vignettes have been included. These vignettes are based on actual families and real events, but have been modified to protect the privacy of both the parents and children.