“Well, you could jump forward again, and”—a thread of ice water down his spine—“you’d wind up in a future where your time machine had never been invented.”

Dean Eagan put his fingers together in a steeple and smiled. “Like this one.”

After the interview, Matt went for a walk to clearhis head. Could he be in a Gцdelian strange loop? It wouldn’t have to be he himself who went back and destroyed the time machine. Anyone capable of traveling into the past could do it, and deposit him in this odd future. A future where he was an anomaly, because the time machine had never been invented and Professor Marsh never stole the Nobel Prize from him.

But thinking about interference from the future made him wonder about the machine’s infuriating singularity. Thousands of copies had been made, and none of them worked; in essence, none of them had the vital, untraceable mistake that turned a graviton/photon calibrator into a time machine.

What if it hadn’t been anything Matt did? What if somebody from the future had come back and modified the machine, so as to make his own present possible? And then someone else from hispresent—or future—came back and destroyed the machine, because his own history required that it not exist? There could be an infinity of closed strange loops like this one.

Or the straightforward explanation could be true. Occam’s Razor. There was a conservative Christian revolution, and when they got into power, they systematically destroyed history in order to rewrite it. The Chinese had done that in ancient times, he remembered from an undergraduate history class—they defeated the kingdom that would become Vietnam in a war, and made the possession of historical documents a crime punishable by death.

But those wereancient times, before universal literacy and printing made books ubiquitous. Somewhere there had to be an old book stashed away, overlooked by the Angels.

He had walked over Longfellow Bridge, which used to carry the Red Line into Boston. At the end of the bridge, he carefully made his way down a rusting spiral stairway to Charles Street.

This is where he had planned to start looking for a buyer for his rare letters from Garcнa Mбrquez and Lincoln. It used to be a street full of antique stores, a couple of them specializing in old documents. Would that commerce have gone underground when history was abolished and rewritten? Maybe the Angels would have gone after them first. The people with actual evidence.

There were more open shops and markets here than he’d seen in the suburbs. More fresh produce, though Arlington and Somerville were closer to the farms. They must get better prices in town, or maybe the city subsidizes them.

The place where he’d bought the Lincoln note to Grant was long closed and boarded up. On the next block, the shop that had sold him the Garcнa Mбrquez letter was still an antique shop, but only in that everything in it was old. It was more like a Salvation Army or Goodwill store in his time—very-used stuff being sold to people who would use it some more.

There was a dusty plastic bookcase with two shelves of Bibles and hymnals and a yellowed old booklet about Boston Baked Beans. There was no date on it, but it might have been pre-S.C.

In his time such a store would have been full of old questionable appliances—the question being, “If this still works, why is it here?”—but the main motif in this one was cast-off clothing, hanging on racks or neatly folded in stacks, according to size. Most of it was pretty threadbare, but he was tempted, since he had only one change of clothes. In this warm weather, he should emulate his graduate assistant and wear the robe with nothing underneath. He was contemplating that memory when a middle-aged male clerk came up, tubby and sweating.

“May I be of service, Professor? I do have an assortment of robes in the back, though none are as fine as yours.”

He hadn’t thought anything of it, but the robe Father Hogarty had bestowed on him was new. How rare was that now?

“Actually, I’m looking for scholarly materials, old things with writing in them.”

He drew back. “Not forbidden books.”

“No, of course not. I mean things like old letters. Written before Christ appeared.”

He scratched his head. “I do have a box of old letters, but they’re probably not that old. I’ll bring them up to the light.”

Matt looked through the coats, thinking of the winter ahead, but of course MIT might provide. He had an appointment tomorrow with the bursar, who would evidently haggle with him over terms of compensation, which took food and shelter into account, so possibly clothing as well. I’ll trade you two Saturdays of one-on-one physics tutoring for long underwear and a winter coat.

The clerk came huffing back with a microwave oven full of loose paper. So some old appliances were still of use.

He cleared off part of a shirt table and began laying out the letters. They seemed all to be post-Second Coming, formal notes of congratulation or condolence. The handwriting was mostly childish script or block printing, not surprising if paper had been a luxury for generations. The wording of the notes was formal and unimaginative, probably copied from an Emily Post-type guide.

Matt looked at about a hundred of them, and there was nothing really interesting. His feet were getting tired, standing. He stacked the letters all back in the microwave and clicked the door shut.

The clerk came up to him with a large padded plastiglass envelope held to his chest. “I do have a curiosity you might want to look at. A holy relic.” He opened the envelope and carefully worked out what looked like an ordinary Bible, and handed it carefully to Matt. “Signed by Jesus Himself.”

“Really.” He opened it, and on the front page was a dark "X,” deeply indented, as if someone had leaned into a ballpoint pen, with JESUS HIS MARK in parentheses.

Matt didn’t know quite how to react. “How much would this be worth, do you think?” he asked the clerk.

“Oh, at least five hundred dollars. I’m not sure I would sell it, though. It makes me feel good just to have it here, and I think it brings luck.”

“Selling it might be unlucky,” Matt said, handing it back. “But couldn’t anybody do this? How do you know it’s authentic?”

“Oh, my father was there when Jesus signed it. Down in Washington.”

That was interesting. Matt’s stomach growled audibly. “Thank you for showing it to me. I’ll be back later, probably buy some winter clothes.”

“God bless.”

Matt nodded gravely. Got to find a ballpoint pen somewhere.

Aromas from the food vendors were tempting,but Martha had told him that a tray would be delivered to his office unless he asked otherwise, so he climbed up the rusty stairs and hurried back onto campus, an appetite-building half hour. This time it was bread and a sausage and a fresh cucumber, all welcome. He wrote a note asking for salt and pepper.

He put the tray and note outside the door and sat down with the natural philosophy book and a piece of paper, and started a rough outline of a physics course that stopped short of special relativity. It was frustrating, but he did map out a thirteen-week schedule. He would never be able to fake the introductory bit about how the workings of nature reflect the handiwork of God, but he could probably ask one of the Fathers to step in for that part. Split the day’s salary with you?

At 3:30 he went back to Building 1 for his appointment with the bursar, a fat little man with a scowl and a squint and the improbable name Father Gouger. He said that in addition to room and board, Matt would be given an allowance for clothing and books. Paper and ink and pen points had to be ordered in advance from Supply. Above that, he’d be paid fifty dollars for every class he taught. The price of two and a half cups of “real coffey.” A good thing he was shaking the habit, and the coffee was lousy, anyhow.