The research literature on dissociative identity disorder is smaller than that on many other Axis I and II disorders. Despite its smaller quantity, however, this literature contains a number of themes and developments of interest to the mental health field as a whole. These themes or topic areas will likely be the focus of research on dissociative identity disorder over the next decade. They include: the relationship among childhood trauma, dissociation, and psychosis; the epidemiology of dissociative identity disorder in a variety of cultures and countries; the psychobiology of trauma and dissociation; memory function in the disorder; controversy about the validity of the disorder; psychologic assessment of dissociation with various measures; and treatment outcome data. Recent research in each of these topic areas published in 2004, 2005, and 2006 is reviewed.