That's just how it is.

But I was feeling so tense I wanted to"Hey, look at the time," Ricky said, giving me a big grin. "I'm late, Mary'll kill me, I've got to run. She's already annoyed because I have to spend the next few days at the fab facility. So I'll be out of town while the maid's gone…" He shrugged. "You know how it is."

"Yeah, I do. Good luck."

"Hey, man. Take care."

We shook hands. Murmured another good-bye. Ricky rolled his cart around the corner of the aisle, and was gone.

Sometimes you can't think about painful things, you can't make your mind focus on them. Your brain just slips away, no thank you, let's change the subject. That was happening to me now. I couldn't think about Julia, so I started thinking about what Ricky had told me about their fabrication plant. And I decided it probably made sense, even though it went against the conventional wisdom about nanotechnology.

There was a long-standing fantasy among nanotechnologists that once somebody figured out how to manufacture at the atomic level, it would be like running the four-minute mile. Everybody would do it, unleashing a flood of wonderful molecular creations rolling off assembly lines all around the world. In a matter of days, human life would be changed by this marvelous new technology. As soon as somebody figured out how to do it.

But of course that would never happen. The very idea was absurd. Because in essence, molecular manufacturing wasn't so different from computer manufacturing or flow-valve manufacturing or automobile manufacturing or any other kind of manufacturing. It took a while to get it right. In fact, assembling atoms to make a new molecule was closely analogous to compiling a computer program from individual lines of code. And computer code never compiled, the first time out. The programmers always had to go back and fix the lines. And even after it was compiled, a computer program never ever worked right the first time. Or the second time. Or the hundredth time. It had to be debugged, and debugged again, and again. And again.

I always believed it would be the same with these manufactured molecules-they'd have to be debugged again and again before they worked right. And if Xymos wanted "flocks" of molecules working together, they'd also have to debug the way the molecules communicated with each other, however limited that communication was. Because once the molecules communicated, you had a primitive network. To organize it, you'd probably program a distributed net. Of the kind I had been developing at MediaTronics. So I could perfectly well imagine them doing programming along with the manufacturing. But I couldn't see Julia hanging around while they did it. The fab facility was far from the Xymos headquarters. It was literally in the middle of nowhere-out in the desert near Tonopah, Nevada. And Julia didn't like to be in the middle of nowhere. I was sitting in the pediatrician's waiting room because the baby was due for her next round of immunizations. There were four mothers in the room, bouncing sick kids on their laps while the older children played on the floor. The mothers all talked to each other and studiously ignored me.

I was getting used to this. A guy at home, a guy in a setting like the pediatrician's office, was an unusual thing. But it also meant that something was wrong. There was probably something wrong with the guy, he couldn't get a job, maybe he was fired for alcoholism or drugs, maybe he was a bum. Whatever the reason, it wasn't normal for a man to be in the pediatrician's office in the middle of the day. So the other mothers pretended I wasn't there. Except they shot me the occasional worried glance, as if I might be sneaking up on them to rape them while their backs were turned. Even the nurse, Gloria, seemed suspicious. She glanced at the baby in my arms-who wasn't crying, and was hardly sniffling. "What seems to be the problem?"

I said we were here for immunizations.

"She's been here before?"

Yes, she had been coming to the doctor since she was born.

"Are you related?"

Yes, I was the father.

Eventually we were ushered in. The doctor shook hands with me, was very friendly, never asked why I was there instead of my wife or the housekeeper. He gave two injections. Amanda howled. I bounced her on my shoulder, comforted her.

"She may have a little swelling, a little local redness. Call me if it's not gone in forty-eight hours." Then I was back in the waiting room, trying to get out my credit card to pay the bill while the baby cried. And that was when Julia called.

"Hi. What're you doing?" She must have heard the baby screaming.

"Paying the pediatrician."

"Bad time?"

"Kind of…"

"Okay, listen, I just wanted to say I have an early night-finally!-so I'll be home for dinner. What do you say I pick up on my way home?"

"That'd be great," I said.

Eric's soccer practice ran late. It was getting dark on the field. The coach always ran practice late. I paced the sidelines, trying to decide whether to complain. It was so hard to know when you were coddling your kid, and when you were legitimately protecting them. Nicole called on her cell to say that her play rehearsal was over, and why hadn't I picked her up? Where was I? I said I was still with Eric and asked if she could catch a ride with anybody.

"Dad…" she said, exasperated. You'd think I had asked her to crawl home.

"Hey, I'm stuck."

Very sarcastic: "Whatever."

"Watch that tone, young lady."

But a few minutes later, soccer was abruptly canceled. A big green maintenance truck pulled onto the field, and two men came out wearing masks and big rubber gloves, with spray cans on their backs. They were going to spray weed killer or something, and everybody had to stay off the field overnight.

I called Nicole back and said we would pick her up.

"When?"

"We're on our way now."

"From the little creep's practice?"

"Come on, Nic."

"Why does he always come first?"

"He doesn't always come first."

"Yes he does. He's a little creep."

"Nicole…"

"Sor-ry."

"See you in a few minutes." I clicked off. Kids are more advanced these days. The teenage years now start at eleven.

By five-thirty the kids were home, raiding the fridge. Nicole was eating a big chunk of string cheese. I told her to stop; it would ruin her dinner. Then I went back to setting the table. "When is dinner?"

"Soon. Mom's bringing it home."

"Uh-huh." She disappeared for a few minutes, and then she came back. "She says she's sorry she didn't call, but she's going to be late."

"What?" I was pouring water into the glasses on the table.

"She's sorry she didn't call but she's going to be late. I just talked to her."

"Jesus." It was irritating. I tried never to show my irritation around the kids, but sometimes it slipped out. I sighed. "Okay."

"I'm really hungry now, Dad."

"Get your brother and get into the car," I said. "We're going to the drive-in." Later that night, as I was carrying the baby to bed, my elbow brushed against a photograph on the living-room bookshelf. It clattered to the floor; I stooped to pick it up. It was a picture of Julia and Eric in Sun Valley when he was four. They were both in snowsuits; Julia was helping him learn to ski, and smiling radiantly. Next to it was a photo of Julia and me on our eleventh wedding anniversary in Kona; I was in a loud Hawaiian shirt and she had colorful leis around her neck, and we were kissing at sunset. That was a great trip; in fact, we were pretty sure Amanda was conceived there. I remember Julia came home from work one day and said, "Honey, remember how you said mai-tais were dangerous?" I said, "Yes…" And she said, "Well, let me put it this way. It's a girl," and I was so startled the soda I was drinking went up my nose, and we both started to laugh.