Let’s call him Frank. “He was in the war” is how adults explained Frank’s odd behavior a generation ago. As he walked through the small town then, his gait was clumsy, his clothes disheveled, and he seemed to go nowhere in particular. One could drive through any part of town and chance to see Frank on the corner, his face at once drawn and blank, as he was waiting to cross a street where the traffic never ceased. Sometimes he carried a paper bag, clutched as though it were filled with precious things. Frank was ghostly, but in an odd way, never threatening. After all, he wasn’t quite there.

One day, in direct contravention of parental orders, a child approached Frank and asked him questions. Was he really in the war? Frank said yes. What did he do? He fought , he said, in the Pacific . Already a devotee of war movies, the child knew what that meant: jungle combat against the most fearsome of enemies, the Japanese. The child’s eyes widened, and the questions came tumbling out.

Frank answered quietly. He described crawling through the jungle, looking for signs of enemy snipers. What signs? asked the child. Rice, Frank said, at the foot of tall jungle trees. Why? Because, Frank replied, rice down below meant a sniper in the tree above.

Time after time in this troubled century, our whole society has made itself forget about the terrible, invisible battle wounds once known as shell shock, later as combat fatigue, and now PTSD—posttraumatic stress disorder

Then what did you do? asked the child. Then, Frank said almost inaudibly, then I went up and got him. And after that Frank’s eyes seem to turn inward. Sensing that he had hurt Frank, the child clumsily did his best to turn the conversation to harmless matters.

I saw Frank’s look again on television not so long ago, during one of several specials on those Vietnam veterans who suffer from what is now called PTSD, or posttraumatic stress disorder. I had been thinking a good deal lately about Frank and his kind, and then all of a sudden there was a man, roughly my own age, staring that look at me from the screen. Strangely, I remembered that I had always thought of Frank as being old.

The Veterans’ Administration hospital in my hometown had many Franks; they all seemed old, but none could have been more than thirty at the time. The VA hospitals still have their Franks. They are the old ghosts of battle. They have been with us for years, perhaps even for centuries, inextricably linked by their suffering. PTSD’s ancestors reach back at least to the American Civil War. Before this century Russian medical scholars were discussing “diseases of the soul” among their soldiery. Their American counterparts wrote at length about “neurasthenia,” but not until the First World War did they apply their knowledge to the military world. During and after that war “neurasthenia” was overtaken by “shell shock” and then by the slightly more sophisticated “war neurosis.” The “war neurosis” of World War I gave way in World War II to the even more imposing “neuropsychiatrie casualty” or the slightly more understanding “combat fatigue.” Indeed, the history of soldiering in the last century and a half can be illuminated by these terms and what they represent.

“Neurasthenia” gave way to “shell shock,” which became “combat fatigue.” Indeed, the history of soldiering in the last 150 years can be illuminated by these terms.

The man I saw on the television screen was telling the interviewer about his unsuccessful life. Not that he was unable to provide for his family; it was only that he often felt estranged, detached from everyone who cared about him. And when the dreams from the old days in Vietnam were so terrible he could not sleep for fear of having them again, he retreated to his own personal redoubt, a small, dimly lit room, filled with relics of his war, that he had cobbled together in his garage. There he spent the night with his demons. Exhausted at dawn, he would climb into his car and commute to work with the rest of us. None of his fellow workers ever knew of his torments. Had he not presented himself to a veterans’ counselor, those torments would be private still.

There were other men on the television program, new Franks all. Several of them had withdrawn altogether from society. Unable to adjust to the civil rhythms of life after their wars in Southeast Asia, they had made their homes in the mountains of the Pacific Northwest, sometimes prowling armed and camouflaged through the night forests. Nearly all were combating a past scarred by drug and alcohol abuse and brushes with the law. They commuted nowhere.

Since the end of the war in Vietnam, Americans have been engaged in a subtle and long-standing negotiation with the memory of that divisive conflict. It was perhaps the most ambiguous of our wars, and its aftermath has been no less so. “Back in the world” after their tours in Vietnam, veterans encountered indifference and sometimes outright hostility.