Nanotechnology was still at the Kitty Hawk stage.

"Come on, Ricky," I said. "How are you really doing this?"

"The technical details aren't that important, Jack."

"What fresh bullshit is this? Of course they're important."

"Jack," he said, giving me his most winning smile. "Do you really think I'm lying to you?"

"Yes, Ricky," I said. "I do."

I looked up at the octopus arms all around me. Surrounded by glass, I saw my own reflection dozens of times in the surfaces around me. It was confusing, disorienting. Trying to gather my thoughts, I looked down at my feet.

And I noticed that even though we had been walking on glass walkways, some sections of the ground floor were glass, as well. One section was nearby. I walked toward it. Through the glass I could see steel ducting and pipes below ground level. One set of pipes caught my eye, because they ran from the storage room to a nearby glass cube, at which point they emerged from the floor and headed upward, branching into the smaller tubes. That, I assumed, was the feedstock-the slush of raw organic material that would be transformed on the assembly line into finished molecules.

Looking back down at the floor, I followed the pipes backward to the place where they entered from the adjacent room. This junction was glass, too. I could see the curved steel underbellies of the big kettles I'd noticed earlier. The tanks that I had thought were a microbrewery. Because that's certainly what it had looked like, a small brewery. Machinery for controlled fermentation, for controlled microbial growth.

And then I realized what it really was.

I said, "You son of a bitch."

Ricky smiled again, and shrugged. "Hey," he said. "It gets the job done." Those kettles in the next room were indeed tanks for controlled microbial growth. But Ricky wasn't making beer-he was making microbes, and I had no doubt about the reason why. Unable to construct genuine nanoassemblers, Xymos was using bacteria to crank out their molecules. This was genetic engineering, not nanotechnology. "Well, not exactly," Ricky said, when I told him what I thought. "But I admit we're using a hybrid technology. Not much of a surprise in any case, is it?" That was true. For at least ten years, observers had been predicting that genetic engineering, computer programming, and nanotechnology would eventually merge. They were all involved with similar-and interconnected-activities. There wasn't that much difference between using a computer to decode part of a bacterial genome and using a computer to help you insert new genes into the bacteria, to make new proteins. And there wasn't much difference between creating a new bacteria to spit out, say, insulin molecules, and creating a man-made, micromechanical assembler to spit out new molecules. It was all happening at the molecular level. It was all the same challenge of imposing human design on extremely complex systems. And molecular design was nothing if not complicated.

You could think of a molecule as a series of atoms snapped together like Lego blocks, one after another. But the image was misleading. Because unlike a Lego set, atoms couldn't be snapped together in any arrangement you liked. An inserted atom was subject to powerful local forces-magnetic and chemical-with frequently undesirable results. The atom might be kicked out of its position. It might remain, but at an awkward angle. It might even fold the entire molecule up in knots.

As a result, molecular manufacturing was an exercise in the art of the possible, of substituting atoms and groups of atoms to make equivalent structures that would work in the desired way. In the face of all this difficulty, it was impossible to ignore the fact that there already existed proven molecular factories capable of turning out large numbers of molecules: they were called cells.

"Unfortunately, cellular manufacturing can take us only so far," Ricky said. "We harvest the substrate molecules-the raw materials-and then we build on them with nanoengineering procedures. So we do a little of both."

I pointed down at the tanks. "What cells are you growing?"

"Theta-d 5972," he said.

"Which is?"

"A strain of E. coli."

E. coli was a common bacterium, found pretty much everywhere in the natural environment, even in the human intestine. I said, "Did anyone think it might not be a good idea to use cells that can live inside human beings?"

"Not really," he said. "Frankly that wasn't a consideration. We just wanted a well-studied cell that was fully documented in the literature. We chose an industry standard."

"Uh-huh…"

"Anyway," Ricky continued, "I don't think it's a problem, Jack. It won't thrive in the human gut. Theta-d is optimized for a variety of nutrient sources-to make it cheap to grow in the laboratory. In fact, I think it can even grow on garbage."

"So that's how you get your molecules. Bacteria make them for you."

"Yes," he said, "that's how we get the primary molecules. We harvest twenty-seven primary molecules. They fit together in relatively high-temperature settings where the atoms are more active and mix quickly."

"That's why it's hot in here?"

"Yes. Reaction efficiency has a maxima at one hundred forty-seven degrees Fahrenheit, so we work there. That's where we get the fastest combination rate. But these molecules will combine at much lower temperatures. Even around thirty-five, forty degrees Fahrenheit, you'll get a certain amount of molecular combination."

"And you don't need other conditions," I said. "Vacuum? Pressure? High magnetic fields?" Ricky shook his head. "No, Jack. We maintain those conditions to speed up assembly, but it's not strictly necessary. The design is really elegant. The component molecules go together quite easily."

"And these component molecules combine to form your final assembler?"

"Which then assembles the molecules we want. Yes."

It was a clever solution, creating his assemblers with bacteria. But Ricky was telling me the components assembled themselves almost automatically, with nothing required but high temperature. What, then, was this complex glass building used for? "Efficiency, and process separation," Ricky said. "We can build as many as nine assemblers simultaneously, in the different arms."

"And where do the assemblers make the final molecules?"

"In this same structure. But first, we reapply them."

I shook my head. I wasn't familiar with the term. "Reapply?"

"It's a little refinement we developed here. We're patenting it. You see, our system worked perfectly right from the start-but our yields were extremely low. We were harvesting half a gram of finished molecules an hour. At that rate, it would take several days to make a single camera. We couldn't figure out what the problem was. The late assembly in the arms is done in gas phase. It turned out that the molecular assemblers were heavy, and tended to sink to the bottom. The bacteria settled on a layer above them, releasing component molecules that were lighter still, and floated higher. So the assemblers were making very little contact with the molecules they were meant to assemble. We tried mixing technologies but they didn't help."

"So you did what?"

"We modified the assembler design to provide a lipotrophic base that would attach to the surface of the bacteria. That brought the assemblers into better contact with the component molecules, and immediately our yields jumped five orders of magnitude."

"And now your assemblers sit on the bacteria?"

"Correct. They attach to the outer cell membrane."

At a nearby workstation, Ricky punched up the assembler design on the flat panel display. The assembler looked like a sort of pinwheel, a series of spiral arms going off in different directions, and a dense knot of atoms in the center. "It's fractal, as I said," he said. "So it looks sort of the same at smaller orders of magnitude." He laughed. "Like the old joke, turtles all the way down." He pressed more keys. "Anyway, here's the attached configuration." The screen now showed the assembler adhering to a much larger pill-shaped object, like a pinwheel attached to a submarine. "That's the Theta-d bacterium," Ricky said. "With the assembler on it."