The world turned upside down in half an hour at dawn, but Jan Karski had no idea then that he was approaching the day of the broken teeth, the slashed wrists, the naked leap from the window, the cyanide pill and the desperate reach for the confessional.

"The war just stopped for me in half an hour," he said when I dropped by his elegant house to visit him. "Then instead of war, all I saw was cows and confusion."

His house, by the way, presents a dark and solid front to the street off MacArthur Boulevard, and you enter off a path to the side. As he moves to let you enter, you see a glass cabinet of carved ivories and jades.

Tall, polished and a little less than outgoing at 65, Karski sat near the glass panels looking on a garden court.

For years now he has been professor of government at Georgetown University, where his classes are packed.

He is not so trusting of humans now as he was then, and does not believe the hogwash he keeps hearing about how idealistic young people are nowadays. It's the work of a lifetime, he has concluded, to become reasonably civilized, reasonably virtuous.

He saw plenty of idealistic young people (hell, he was young himself when the war started 40 years ago tomorrow) who did not behave well in the crunch. The Poles who for cash turned over Jews to the Germans. The two good-looking young Germans he saw in Warsaw using Jews for a bit of sport -- target practice. Or, for that matter, the Jews who in agony called for slaughtering German civilians.

No, there is no point assuming mankind is very noble, and he said once, out of the blue:

"I could have been a bank robber." Instead, life took him elsewhere. He awoke to a shower of bombs the morning of the invasion.

He was a lieutenant in the mounted artillery. The horses would always appeal to gentlemen. Horses (not that he said so) always smell good.

But as Karski said, they were not very effective against German bombs or tanks. He was full of anger, and no doubt humiliation, to notice along with everybody else that the Germans were winning in less time than it takes to drive a truck through a field of forget-me-nots. Karski had not fired a shot, and here he was fleeing to the east with half the rest of Poland.

In a few days he reached the Red Army, heading west, and (after confusion) found himself a Russian prisoner, on his way to a camp far inside the Soviet Union.

One thing about war that's hard to understand is that often you have no idea what's going on. In Karski's case, for example, when the bombs fell there were no reliable newspapers to explain it all.

His officer's sword would have been excellent for slicing Hitler's head off, but that was not an option as the train bore him farther into Russia, away from home.

"The Russians never abused me, or any of the others," he said. As captors go, they were relatively unmonstrous. He cleaned out pots in the kitchen, demeaning for an officer but Kraski made up his mind to survive.

"Enormous pots," he said. "You had to get inside them to clean them. I could eat anything I could scrape from the sides. I was never hungry."

But escape seemed impossible. He learned that if he were a Polish private, instead of an officer, he could request transfer back to the German side. So he disguised himself as a private, told as many lies as necessary, and found himself on a train heading back into Poland.

There was a bridge, with Poles on each side.

Half of them were requesting transfer to the Russian side, half to the German. They met at the middle of the bridge.

"It was very efficient," Karski said. "They counted us off just like cattle, head for head. The Poles heading for the Russian side hollered at us, 'You dirty fascists are crazy. You better stay where you are.'"

Karski, to tell the truth, was not keen to be a German prisoner either, but thought escape might be possible from Poland, while it was clearly impossible from a camp hundreds of miles inside Russia.

And sure enough, escape was possible from the train carrying the Poles west toward forced labor in Germany, or towards prisoner camps.

"There was no point trying to escape when the train stopped," Karski said, "but when it was going about 30 kilometers an hour it seemed possible. Dozens of us were jumping, and they were shooting."

Usually they missed, of course. Karski, after some adventures, got back to Warsaw where he fell into the Polish underground by accident and was pleased.

He was a little surprised. Still, here was his first opportunity to risk his life for his country. He was still smarting to think the war had been going on only a few weeks and already he had been prisoner of both Russians and Germans and had done precisely nothing to help Poland.

He was sent to Agners, the French provincial center of the Polish government (later the government in exile centered in London).

He was a courier between the Polish underground and the Polish government in exile. He learned how to lie quickly and plausibly, how to memorize his "legends" -- those stories that were supposed to explain his reason for being wherever he happened to be.

He learned that to go to France, say, you might take a very roundabout route. When you were very tired and cold, maybe it was safe to rest at a peasant's hut, maybe not. He learned you better guess right.

Once he guessed wrong and found himself (June 1940) in Gestapo hands in the Slovakian city of Preshov.

None of his legends worked. After a bit he was turned over to an SS officer, who immediately saw through all Karski's fabrications.

That officer said it was nice to meet a gentleman like Karski in that Godforsaken mess of a country, and urged cooperation with the Germans who (he went on) meant no harm at all to the Poles (merely to annex them to the German empire).

"Believe me, I took to him," Karski said, inhaling a cigarette, of which he smokes a great number.

But when it became clear Karski was not for some reason, going to betray his country, things changed.

The good-looking German officer changed tactics "just as in the movies," Karski went on.

"They were hitting me behind the ears with rubber truncheons. They broke my ribs. They knocked by teeth out."

He was alone for a bit, to recover sufficiently for further persuasion, and took out a blade he had concealed in his shoe and slashed both his wrists.

"You have no idea how hard it is," he said. "The Romans often succeeded," he said.

"Of course," I went along."Petronius, after all."

"Yes," Karski said, "but it's by no means easy. I finally got the blood really coming out, but it takes a long time."

A Slavic guard found him on his cot full of gore, and Karski was sent to a hospital.

"A doctor told me, by the way, that people try it all the time, the wrists, and it never works."

But to get on.

"They sent me back to Poland, for further interrogation. Through incredible conincidence, it was a city I knew well, and where I had underground contacts. Let me say that when I was undergoing torture, all the time I was surrounded by sympathy, good Slovaks, but there was nothing they could do."

At the hospital in Poland, where they worked on his wrists and other injuries, he was assisted (up to a very discreet and limited point) by sympathetic doctors and nurses who urged him to stay as sick as possible as long as possible.

He concentrated on it, and found himself sick indeed, since then he has never discounted the power of the mind in illness. The Germans had guards continually at the hospital and he could not see how to make contact with his underground agents.

There was a chapel. Karski one day began to scream and carry on:

"I'm going to die. I want to be confessed," and the truth is he was annoyed at the wrist-slashing episode which not only was a sin, which was bad enough, but had not even worked.

The short of it is they wheeled him down to confession and afterward he took the one chance he had and asked the priest to get a message to his underground woman aide saying he was at the hospital. Nothing more.

"My son," said the priest (and Karski is quite good at sonorous imitations) "you have no right to ask a priest any such thing. I am your confessor," and delivered a small homily on the wrongfulness of using the holy church for less than divine purposes.

"Now what was that address?" the priest concluded.

The woman from the underground arrived disguised as a nun.

"I can't take torture," Karski was able to convey to her, as she freshened his pillows and patted things as nurses do.

"Here is a cyanide pill," the girl said. "Don't use it except in extremest need. We are going to try to free you."

How, I asked Karski, could a patient under guard be freed?

"Bribery," he said. Plenty of lower- and middle-level Nazis were open to bribes, he said. As an American, I can scarcely believe it, but Karski insisted.

A doctor whispered instructions:

"And when you get to that place you see an open window with a rose in a glass of water. You must be naked, and you must jump out the window. Do not think twice."

Karski, naked, found the window and jumped. Two pairs of arms bore him up, dressed him in the clothes they brought, and got him back to Warsaw and his work in the underground.

In November 1942 he was sent to London to give a report on treatment of the Jews in Poland.

To prepare himself, he met with Jewish leaders who told him in great detail what was happening.Karski said he would have to see these things with his own eyes, and the Jewish leaders agreed he must, though (Karski went on) they were sorry he would have to take such memories through life with him.

He was smuggled into the Warsaw ghetto. Three hundred thousand Jews had already been shipped out for death, he was told, and about 5,000 a day were still going. He was taken into a building with a courtyard and invited to peer through slats of a window blind. There, he said, he saw the fine-looking German youths shooting old Jews for sport.

"The hunt," he said. For a long time Karski said he vomited when he thought of the ghetto and the Belzek death camp, which he also visited while it was operating.

"Can I get you a drink?" he asked. He got himself one.

He was smuggled into the death camp, out from Warsaw, disguised as an Estonian guard. It was carefully set up. The main thing was not to run into any other Estonian guards who might recognize he was not one of them.

In the camp he was able to see how it worked. The ground was littered with weakened bodies. In the several days between arriving at the camp and dying, the Jews were not given anything to eat or drink, Karski said, so they were crazed. He said he saw Jews packed into railway cars, 120 to the car (meant to hold 40 men and eight horses). The cars were floored with a layer of quicklime. The moisture of the bodies activated it. The doors were shut and the cars moved out a short distance to an open place.

After three or four days, the cars were opened.No cyanide or bullets had been wasted. Able-bodied Jews were forced to clean out the cars of their dead bodies (which were burnt) and the cars were sprinkled with quicklime (for the Nazis were good at hygiene) and returned for the next loads.

Karski went to the government-in-exile in London and gave his report, and saw many dignitaries, including Lord Selbourne who was in charge of European underground resistance. Lord Selbourne, Karski said, told him he was doing a magnificent job. In World War I, Karski said Selbourne said, there were atrocity stories about Belgian babies, and His Majesty's Government of course knew they were false but did nothing to stop these rumors. The implication, Karski felt, was that Selbourne did not believe the stories about the Jews either, but thought they had propaganda value.

Karski also reported in person to Anthony Eden and numerous other officials.

He was sent to the United States where he had face-to-face meetings with President Roosevelt, Herbert Hoover, Cordell Hull, Henry Stimson, Francis Biddle, three archbishops and the apostolic delegate, leading rabbis, Walter Luppmann, the publisher of the New York Herald Tribune and others.

"My talk to Roosevelt was at the White House. I answered his questions, told him everything about the Jews, sparing nothing. I found it helped sometimes to shut my eyes and speak the facts as if I were a machine," he said.

I sensed he did not much like Roosevelt, who responded:

"Tell your nation we shall win the war" and another lofty thing to two, not mentioning the immediate plight of the Polish Jews who expected to be dead before the war ended.

"Justice Frankfurter asked me if I knew who he was and I said of course, and he said, 'Do you know I am a Jew?'

"I said I knew that. He asked me to tell him everything I knew about the Jews, and when I finished he said some complimentary things but then said:

"I can't believe you.'

"The Polish ambassador was with me, and he told the justice that I was there under the authority of the Polish government and there was no possibility in the world I was not telling the unadorned truth.

"Justice Frankfurter stretched his arms out, his hands up with palms out, and said, 'I did not say this young man is lying. I said I cannot believe him. There is a difference.'"

Later Karski earned a doctorate in government at Georgetown University in three years (he already had two masters degrees earned before the war) and began teaching there and has continued ever since, with time out for a year as visiting professor at Columbia University in New York, and lecture sessions in Africa.

At one point his wife entered with a great sack of groceries. Mon Dieu, it's hot outside. She is a soft, very feminine sort of person, a concert dancer who for years taught here. She loves abstract impressionist pictures and has a number of them like sunbursts against the dead-white walls.

Karski does not share her passion for painting, and there is a pretty sharp line in the library between her books and his. She is a Polish Jew, and Karski said if he starts to get the better of her in debate, she ends it:

"Well. If you had even a drop of Jewish blood in you you'd understand and wouldn't be so dumb." Karski has not yet figured how to answer that reasonable argument and has about given up.

"Well, now," I said, allowing things to settle a bit, "is the world insane, is there anything special about our century or are we merely more of the same, with better transportation and technology?"

"There is temporary insanity," Karski said, "and we are familiar with it in individuals. It can also afflict whole nations. Hundreds of factors contribute -- the mass media, the technics of propaganda. It looks like some bad play. I think evil and hatred are in our natures, a trend through all generations.

"And then here comes Francis from Assisi. So you have always another trend, too. Bad is as natural to us as good, but there is good which is also natural.

"I'm not a theologian; my theology may be off. There is some divine order. Which I actually believe. God created the devil as well as angels, and I say I have a choice, Karski.

"Even the devil does good, because we learn what evil is. We are all schizophrenes, bad and good. The potential for evil is always with us, but we have will.

"God made us this way somehow," and he lit another cigarette, and the light was beginning to go a little by the late afternoon. "Only the road is so painful."