I was troubled about those twenty-one extra Dajanis, but the smart alecks in the class quickly figured out why they hadn’t all jammed up together here in now-time. It had to do with the fundamental limitations of the Benchley Effect in achieving down-the-line, or forward, travel.

My classmate Mr. Burlingame explained it all to me after class. It was his quaint way of trying to seduce me. He didn’t score, but I learned a little time theory.

When you go down the line, he told me, you can come forward only as far as you had previously jumped up the line, plus the amount of absolute time elapsed during your stay up the line. That is, if you jump from March 20, 2059, say, to the spring of 1801, and spend three months in 1801, you can come forward again as far as June 20, 2059. But you can’t jump down the line to August, 2059, nor can you jump to 2159 or 20590.

There is no way at all to get into your own future.

I don’t know why this is so. Mr. Burlingame placed his pale palm on my knee and gave me the theoretical substructure for it, but I was too busy fending him off to follow it.

In fact, although Dajani later spent three sessions simply instructing us on the mechanics of the Benchley Effect, I still can’t say for sure how the whole thing works, or why, or even if. At times I suspect I’ve dreamed it all.

Anyway, there aren’t twenty-two Dajanis in now-time because whenever Dajani made the Crucifixion run, he always jumped back to now-time at a point somewhat prior to his next departure for the past. He couldn’t help himself about that; if you go up the line in January, spend a couple of weeks in an earlier era, and come back, you’ve got to land in January or maybe February of the year you started from. And if your next jump isn’t scheduled until March, there’s no way you can overlap yourself.

So the Dajani who escorted tourists to Golgotha was always the “same” one, from the point of view of people in now-time. At the other end of the jump, though, a couple dozen Dajanis have been piling up, since he keeps jumping from different points in now-time to the same point in then-time. The same happens to anybody who makes repeated jumps to one spot up the line. This is the Paradox of Temporal Accumulation. You can have it.

When not wrestling with such paradoxes I passed my time pleasantly in pleasure, as usual. There were always plenty of willing girls hanging around Sam’s place.

In those days I chased crotch quite a bit. Obsessively, even. The pursuit of cunt occupied all my idle hours; it seemed a night wasted if I hadn’t slid down that slippery slope at least once. It never occurred to me that it might be worthwhile for me to seek a relationship with a member of the opposite sex that was more than six inches deep. What they call “love.”

Shallow, callow youth that I was, I wasn’t interested in “love.”

On the other hand, maybe I wasn’t so shallow. For now I’ve tried “love” and I don’t see where I’m the happier for it. I’m a lot worse off than before, as a matter of fact.

Of course, nobody told me to fall in love with someone who lived up the line.

Lieutenant Bruce Sanderson of the Time Patrol came to our class one day to explain to us the perils of daring to meddle with the fixity of past time.

The lieutenant looked his part. He was the tallest man I had ever seen, with the widest shoulders and the squarest jaw. Most of the girls in the class had instant orgasms when he entered, as did Mr. Chudnik and Mr. Burlingame. He took a spread-legged stance, back to the wall, ready for trouble. His uniform was gray. His hair was red and cut very short. His eyes were a soulless blue.

Dajani, himself guilty of transgressing, himself a victim of the Time Patrol’s diligence, slithered into a corner of the classroom and yielded the floor. I saw him peering balefully at the lieutenant through his dark glasses.

“Now then,” Lieutenant Sanderson said, “you know that our big job involves maintaining the sanctity of now-time. We can’t let all kinds of random changes get introduced into our past, because that’ll mess up our present. So we have a Time Patrol that monitors the whole territory up the line and makes sure that everything happens according to the books. And I want to say, God bless the men who legislated the Time Patrol into existence.”

“Amen,” said the penitent Dajani.

“Mind you, it isn’t that I’m thankful for the job I have,” the lieutenant continued. “Although I am because I think it’s the most important job a human being can have, preserving the sanctity of his now-time. But when I say God bless the men who said we had to have a Time Patrol, it’s because those men are responsible for saving everything that is true and good and precious about our existence. Do you know what might have happened without a Time Patrol? What sort of things unscrupulous villains might have done? Let me give you a few examples.

“Such as going back and killing Jesus, Mohammed, Buddha, all our great religious leaders, when they were still children and hadn’t had time to formulate their wonderful and inspiring ideas.

“Such as warning the great villains of our history of trouble in store for them, and thus allowing them to cheat destiny and continue doing harm to humanity.

“Such as stealing the art treasures of the past and preventing millions of people over many centuries from enjoying them.

“Such as engaging in fraudulent financial operations resulting in the bankrupting of millions of innocent investors who happened not to have information on future stock prices.

“Such as giving false advice to great rulers and leading them into terrible traps.

“I mention all these examples, my friends, because they are things that have actually happened. They all come from the files of the Time Patrol, believe it or not! In April, 2052, a young man from Bucharest used an illegally obtained timer to shunt up the line toA.D. 11 and poison Jesus Christ. In October, 2043, a citizen of Berlin traveled back to the year 1945 and rescued Adolf Hitler just before the Russians entered the city. In August, 2049, a woman from Nice jumped to the era of Leonardo da Vinci, stole the unfinished Mona Lisa, and hid it in her beach cabana. In September, 2055, a New York man journeyed to the summer of 1929 and netted close to a billion dollars by selling stock short. In January, 2051, a professor of military history from Quebec journeyed to 1815 and, by marketing to the British what purported to be the French strategic program, caused the defeat of the Duke of Wellington by the forces of Napoleon at the Battle of Waterloo. And therefore—”

“Wait a second!” I heard myself say. “Napoleon didn’t win at Waterloo. Christ wasn’t poisoned inA.D. 11. If the past was really changed as you just said, how come no effects of it have been felt in now-time?”

“Aha!”cried Lieutenant Sanderson. He was the best crier of “Aha!” I have ever heard. “The fluidity of the past, my friend, is a double-edged blade. If the past can be changed once, it can be changed many times. Now we come to the role of the Time Patrol.

“Let us consider the case of the deranged person who assassinated the young Jesus. As a result of this shocking deed, Christianity did not emerge, and much of the Roman Empire was ultimately converted to Judaism. The Jewish leaders of Rome were able to steer the empire away from its collapse of the fourth and fifth centuriesA.D., turning it into a monolithic theocratic state that controlled all of western Europe. However, the Byzantine Empire did not develop in the East, which instead was ruled from Jerusalem by a schismatic Hebrew sect. In the tenth century a cataclysmic war between the forces of Rome and those of Jerusalem resulted in the annihilation of civilization and in the takeover of all of Europe and Asia by Turkish nomads, who proceeded to construct a totalitarian state that, by the twenty-first century, had become the most repressive in human history.