Their skins were different colors but they all belonged to the same ethnic group: Military. Black kids didn't talk like black kids. Asian kids didn't bust their asses to excel in school. White kids, by and large, didn't have any problem getting along with the black and Asian kids. And girls knew their place. They all had the same moms with the same generous buttocks in stretchy slacks and the same frosted-and-curling-ironed hairdos, and they were all basically sweet and endearing and conforming and, if they happened to be smart, they went out of their way to hide it.

So the first time Hiro saw Juanita, or any other girl like her, his perspectives were bent all out of shape. She had long, glossy black hair that had never been subjected to any chemical process other than regular shampooing. She didn't wear blue stuff on her eyelids. Her clothing was dark, tailored, restrained. And she didn't take shit from anyone, not even her professors, which seemed shrewish and threatening to him at the time.

When he saw her again after an absence of several years -a period spent mostly in Japan, working among real grown-ups from a higher social class than he was used to, people of substance who wore real clothes and did real things with their lives - he was startled to realize that Juanita was an elegant, stylish knockout. He thought at first that she had undergone some kind of radical changes since their first year in college.

But then he went back to visit his father in one of those Army towns and ran into the high school prom queen. She had grown up shockingly fast into an overweight dame with loud hair and loud clothes who speedread the tabloids at the check-out line in the commissary because she didn't have the spare money to buy them, who popped her gum and had two kids that she didn't have the energy or the foresight to discipline.

Seeing this woman at the commissary, he finally went through a belated, dim-witted epiphany, not a brilliant light shining down from heaven, more like the brown glimmer of a half-dead flashlight from the top of a stepladder: Juanita hadn't really changed much at all since those days, just grown into herself. It was he who had changed. Radically.

He came into her office once, strictly on a business matter. Until this point, they had seen each other around the office a lot but acted like they had never met before. But when he came into her office that day, she told him to close the door behind him, and she blacked out the screen on her computer and started twiddling a pencil between her hands and eyed him like a plate of day-old sushi. Behind her on the wall was an amateurish painting of an old lady, set in an ornate antique frame. It was the only decoration in Juanita's office. All the other hackers had color photographs of the space shuttle lifting off, or posters of the starship Enterprise.

"It's my late grandmother, may God have mercy on her soul," she said, watching him look at the painting. "My role model."

"Why? Was she a programmer?"

She just looked at him over the rotating pencil like, how slow can a mammal be and still have respiratory functions? But instead of lowering the boom on him, she just gave a simple answer: "No." Then she gave a more complicated answer. "When I was fifteen years old, I missed a period. My boyfriend and I were using a diaphragm, but I knew it was fallible. I was good at math, I had the failure rate memorized, burnt into my subconscious. Or maybe it was my conscious, I can never keep them straight. Anyway, I was terrified. Our family dog started treating me differently - supposedly, they can smell a pregnant woman. Or a pregnant bitch, for that matter."

By this point, Hiro's face was frozen in a wary, astonished position that Juanita later made extensive use of in her work. Because, as she was talking to him, she was watching, his face, analyzing the way the little muscles in his forehead pulled his brows up and made his eyes change shape.

"My mother was clueless. My boyfriend was worse than clueless - in fact, I ditched him on the spot, because it made me realize what an alien the guy was - like many members of your species." By this, she was referring to males.

"Anyway, my grandmother came to visit," she continued, glancing back over her shoulder at the painting. "I avoided her until we all sat down for dinner. And then she figured out the whole situation in, maybe, ten minutes, just by watching my face across the dinner table. I didn't say more than ten words - 'Pass the tortillas.' I don't know how my face conveyed that information, or what kind of internal wiring in my grandmother's mind enabled her to accomplish this incredible feat. To condense fact from the vapor of nuance."

Condense fact from the vapor of nuance. Hiro has never forgotten the sound of her speaking those words, the feeling that came over him as he realized for the first time how smart Juanita was.

She continued. "I didn't even really appreciate all of this until about ten years later, as. a grad student, trying to build a user interface that would convey a lot of data very quickly, for one of these baby-killer grants." This was her term for anything related to the Defense Department. "I was coming up with all kinds of elaborate technical fixes like trying to implant electrodes directly into the brain. Then I remembered my grandmother and realized, my God, the human mind can absorb and process an incredible amount of information - if it comes in the right format. The right interface. If you put the right face on it. Want some coffee?"

Then he had an alarming thought: What had he been like back in college? How much of an asshole had he been? Had he left Juanita with a bad impression?

Another young man would have worried about it in silence, but Hiro has never been restrained by thinking about things too hard, and so he asked her out for dinner and, after having a couple of drinks (she drank club sodas), just popped the question: Do you think I'm an asshole?

She laughed. He smiled, believing that he had come up with a good, endearing, flirtatious bit of patter.

He did not realize until a couple of years later that this question was, in effect, the cornerstone of their relationship. Did Juanita think that Hiro was an asshole? He always had some reason to think that the answer was yes, but nine times out of ten she insisted the answer was no. It made for some great arguments and some great sex, some dramatic failings out and some passionate reconciliations, but in the end the wildness was just too much for them - they were exhausted by work - and they backed away from each other. He was emotionally worn out from wondering what she really thought of him, and confused by the fact that he cared so deeply about her opinion. And she, maybe, was beginning to think that if Hiro was so convinced in his own mind that he was unworthy of her, maybe he knew something she didn't.

Hiro would have chalked it all up to class differences, except that her parents lived in a house in Mexicali with a dirt floor, and his father made more money than many college professors. But the class idea still held sway in his mind, because class is more than income - it has to do with knowing where you stand in a web of social relationships. Juanita and her folks knew where they stood with a certitude that bordered on dementia. Hiro never knew. His father was a sergeant major, his mother was a Korean woman whose people had been mine slaves in Nippon, and Hiro didn't know whether he was black or Asian or just plain Army, whether he was rich or poor, educated or ignorant, talented or lucky. He didn't even have a part of the country to call home until he moved to California, which is about as specific as saying that you live in the Northern Hemisphere. In the end, it was probably his general disorientation that did them in.

After the breakup, Hiro went out with a long succession of essentially bimbos who (unlike Juanita) were impressed that he worked for a high-tech Silicon Valley firm. More recently, he has had to go searching for women who are even easier to impress.