What was it then? Suddenly he knew – it was the girl who had lived at the other end of his block when he was growing up.

Mary Elizabeth was her name. He remembered listening to her as she skipped rope with her friends in the cul-de-sac that the kids in the neighborhood used as their playground. "Why are you blind?" the other kids would ask him. "Hey, why are you blind?" placing a stress on the word that made it obvious they were taunting him. He had learned that they would keep taunting him no matter how he answered, so it was better just to keep quiet.

But Mary Elizabeth had never asked him the question at all – not once.

He couldn't have been older than eight or nine at the time, but he was in love with her – in love not only with how nice she was to him, but with the sound of her voice, and the way that her sandals flapped against the underside of one of her feet but not the other as she walked, and with the smell of cocoa butter that came from her skin whenever she was jumping rope and had begun to work up a sweat.

One day – he didn't know why – he braced up his courage to tell her so. He had been drinking warm Coca-Cola out of a thermos his mother had given him, tasting the way the rusty metal flavored the soda, and was still holding the cap in his hand. As she walked by with her friends, he said her name, "Mary Elizabeth."

But before he could finish with "I love you," as he had planned to, she interrupted him. "Here you go," she said.

He felt the weight of the coin landing inside his thermos cap before he heard it.

The other kids began to laugh, but Mary Elizabeth told them to shut up. "It isn't funny, you guys. Leave the poor thing alone."

The poor thing – that was what she called him.

He might have been angry with Mary Elizabeth, or so upset that he burst into tears. He was that kind of child. He might have loved her all the more for defending him. He was that kind of child, too. But instead he had just stood there embarrassed, his courage dying out inside him as the girls took up their jump ropes and began to chant again: "Big Mac, Filet o' Fish, Quarter Pounder, french fries, icy Coke, thick shake, sundaes, and apple pies."

It was amazing to think that he had constructed an entire lifetime out of moments like this. He had strung them together like beads, he thought, choosing only the ones that were the most painful to him, the ones that left a sandpapery grit on his fingers.

So intently was he remembering the incident that he did not realize he had come to the corner where the curb dropped off into a pothole, and when he stepped off the edge, his foot caught the side. He almost fell over, but he was able to stop himself with one quickly planted step. He could tell right away that he had twisted a muscle in his knee – not badly, but enough so that he should have taken his weight off of it for an hour or two. Still, he kept walking, so that no one would stop to ask him if he needed help.

He had gone another three blocks before he realized that he had already passed the door to his building. It was almost a quarter mile behind him now, just past the silent movie theater and the library with the willow tree on the front walk. Sometimes, like everybody else, he was afraid he was losing his mind.

The small section of Clapboard Hill Road that edged up alongside the riverbank before it curved away and rose into the city was the next block to disappear. It was followed soon after by the lowermost corner of the golf course, including holes nine, eleven, twelve, and fourteen. After that it was an old mattress-spring warehouse on the opposite side of the monument district, and then the bottom half of M Street, and then, a few days later, it was the river itself. The blind man began to think of the wall as a slowly shrinking bubble that was slicing away at the city from all directions. He had no direct evidence for the idea, but he couldn't keep himself from imagining it: a giant bubble, gradually drawing together along its circumference, rising up from below as it sank down from above. He wasn't sure what would happen when it finally shrank to a single point.

Sometimes, when his curiosity got the better of him, he would go to the park to listen to what other people were saying about the phenomenon. Nobody could see anything, ever – which was to say that they could see, precisely, nothing. Some of them said that they visited the outer limits of the district regularly, every day or every few days. Some of them said that they stayed as close to the center of the city – or what remained of the city – as possible. A few of them confessed that they were frightened, but most of them simply seemed resigned to the idea of waiting to see what would happen.

He met one man who told him that he walked the entire periphery of the bubble (though he called it the circle, instead) every morning before he went to work. Every day another little piece of the city went missing, he said, and every day his walk became that much shorter. The man was a dentist, and when the blind man opened his mouth to yawn, he commented, "Those molars of yours look absolutely terrible. You should come by my office sometime and let me take a better look at them." As he left, he handed the blind man a business card with a perfectly matte surface. The card was illegible to the blind man's fingers, so he threw it away.

After a while, it seemed, somebody would always begin to compare the disappearances along the border of the city to the crossing, suggesting that the city was undergoing a crossing of its own, that it was dreaming itself out of existence, or moving from one sphere of being into another. Though the metaphor was not an obvious one, it was certainly common, which made him think that there might be some truth to it.

Soon after the subject of the crossing was mentioned, the blind man would invariably start talking about the desert again. He couldn't help himself. The experience had nearly broken him in two, and it was one of the few things he was certain he would never forget.

He was passing by the open door of a restaurant one day, after a long morning in the park, when he heard two men arguing about whether the people in the city should more properly be considered bodies or spirits. "Of course we're bodies," one of the men said. "Bodies and nothing but. Have you ever heard of a spirit that ate hamburgers and chili dogs for lunch, a spirit that got leg cramps in the middle of the night?"

The other man answered, "How can you be so sure what spirits do and don't do? Have you ever been one before?"

"I know because of the world's entire history of spirit commentary. People have been writing about spirits for thousands of years, Puckett. What do you think all that writing was about? It was about constructing the spirit, that's what – building the concept from scratch. I would say I've learned as much about the idea of the spirit as the next guy over the years, and let me tell you" – he made the hollowed-out double thumping sound that meant he was striking his chest – "this isn't it."

"But surely," the second man said, "surely if there's one thing that everybody who's ever written about the spirit agrees on, it's that when you die, your spirit is released from your body. That's got to be right at the center of the concept, doesn't it?"

"But who's to say we haven't been reembodied?"

"I'm to say it. Me. Right here."

There was a flaw at the heart of their discussion, the blind man realized. They were mistaking the spirit for the soul. Many people tended to use the words casually, interchangeably, as though there was no difference at all between them, but the spirit and the soul were not the same thing. The body was the material component of a person. The soul was the nonmaterial component. The spirit was simply the connecting line.