Personality disorders (PDs) have been identified in every edition of the Diagnostic and Statistical Manual (DSM) of the American Psychiatric Association (APA). Specific diagnostic criteria were identified to define each of the PDs in 1980 in DSM-III, and the PDs were placed on Axis II in this first multiaxial version of the DSM. It is interesting that the two main diagnostic categories on Axis II were the PDs and, so called at the time, mental retardation. Although placement of these two groups on Axis II was multidetermined, it is easy to imagine that they were both seen as “life sentences”—one thought to be “psychogenic” and the other “biological” and heritable but both being longstanding and unlikely to change. We know now that some of these distinctions and assumptions are inaccurate. The PDs are moderately heritable conditions, comparably so to such disorders as major depression and schizophrenia. As is true in all of medicine, the combination of heritable risk and environmental stress can lead to the development of an illness, a formula that applies to the PDs as well as to other psychiatric disorders. The PDs generally have their onset in late adolescence or early adulthood, and it is often early life trauma or neglect that impairs the normal attachment process, thus interfering with the development of a healthy sense of self and of healthy and mutually rewarding interpersonal relationships.