Depersonalization is a dissociative disorder, causing alteration in the perception or experience of the self and a detachment from reality. This is a fascinating and clinically relevant phenomenon neglected within psychiatry. Far from being a rare condition, it can be as prevalent as schizophrenia or bipolar disorder and frequently occurs in association with other neuropsychiatric conditions. This is an up-to-date review of depersonalization, dealing with the subject from a wide range of perspectives and covering historical, conceptual, clinical, trans-cultural, pharmacological and neurobiological factors. It discusses recent neuroimaging studies providing fresh insights into the condition and opening up new opportunities to manage the symptoms with pharmacologic and psychotherapeutic interventions. As a reference book on depersonalization it represents a timely and highly relevant contribution to fill an unjustified gap in the psychiatric literature. It will be relevant to psychiatrists and clinical psychologists, as well as primary care practitioners, neurologists and psychiatric nurses.