This book discusses the experience of loneliness over time; how it was been understood throughout past research and its conceptualization up to the present research. This book extends previous understanding of THE LONELINESS EXPERIENCE over time and between cultures or sub-cultures by presenting a study that examined the experience of three hundred participants in two drug rehabilitation groups and was compared to the experience of individuals in the general population. Factors which compose the multidimensional loneliness experience are Emotional Distress, Social Inadequacy and Alienation, Growth and Discovery, Interpersonal Isolation and Self-Alienation. Overall, significant differences were found between the detoxification group and the general population, with a significant difference found between methadone users and the general population on Self-Alienation. This book follows a typical format found in empirical research and to that end, it is geared more for the academic audience. However, anyone wishing to understand loneliness experiences over time will find this book to provide that type of historical account.