Psychosis is considered the most debilitating psychiatric condition. It presents a heavy burden of suffering in terms of its prevalence, morbidity, and potentially high personal, familial and social costs. In effect, it has in the past decades received increased attention by investigators. Despite the continually accumulating research on this puzzling and diverse disorder, its precise nature remains poorly understood. This book integrates major up-to-date advances in theory and research, and it is conceptualised as a useful tool for advanced clinical psychology students, researchers, and other mental health professionals, for whom a tool on Psychosis could prove useful in their scientific inquiry and/or evidence-based professional practice.