It should be apparent to even the most casual observer that psychotropic medications revolutionized the practice of medicine. Not as readily apparent, however, is the irony that this great revolution began with a minuscule nanometer adjustment. In creating chlorpromazine, the French chemist Paul Charpentier in effect moved promethazine’s side-chain nitrogen from the second to the third carbon atom. This new position inadvertently bestowed to chlorpromazine an antipsychotic potential not shared by promethazine. Dr. Charpentier’s fortuitous tinkering became the basis for one of medicine’s great awakenings. Yet more ironic, it was a French naval surgeon, Dr. Henri Laborit (here also described as an anesthesiologist), not a psychiatrist, who first noted the new drug’s psychotropic activity (though he sensibly sought the collaboration of psychiatrist colleagues at his own Val-de-Grace Hospital for confirmation). After impressive results in their psychotic patients (it was reportedly given in combination with barbiturates), chlorpromazine was recommended to Drs. Delay and Deniker at St. Anne’s Psychiatric Hospital in Paris. These psychiatrists administered it alone to their patients and validated the therapeutic breakthrough with a promptness that would not be seemly today.