A phencyclidine derivative developed by Parke-Davis represented an attempt to mimic phencyclidine anesthesia without inducing the severe psychomimetic reactions of its parent compound. Initial reports were promising and received great enthusiasm. At high doses, the drug was found to provide profound analgesia whilst preserving airway reflexes. It induced reliable amnesia, yet could be delivered as a simple injection. It was claimed at the time that this anesthetic heralded a new phase in the history of anesthesia. Today, over 40 years since the anesthetic was introduced at Michigan, there has been a resurgence of interest in this old drug. A growing number of investigators are studying the effects of anesthesia on human subjects. There is currently tremendous interest in anesthesia as an opioid sparing agent, a model for schizophrenia, an antidepressant, and as an N-Methyl D-Aspartate (NMDA) antagonist in complex regional pain syndromes.