I do not remember being much aware of this at the time. In fact, I feel sure that I was oblivious to details of my surroundings that did not relate directly to my work. The lab still possessed first-rate equipment. My own living quarters, a mile and a half away, consisted of two rooms in a four-story walk-up with a shared bathroom and inadequate hot water, but it satisfied my needs. Had I been asked, I would surely have said that I was perfectly happy.

How much of human happiness stems from an ignorance of what we are missing? I had tried sex with women in four brief affairs since the age of twenty, and found it fairly enjoyable but inferior in excitement to the intoxicating pleasures of research. I felt no urge toward sex with members of my own gender. Thus I had no partner or companion, and with no one else to set the pattern of my days it was my habit to rise late and work until I felt ready to stop. Usually that was after midnight, and often far beyond.

Sometimes, as on this day, dawn was touching the horizon as I left the institute and headed home. The Scantlings’ rigidity had one beneficial effect: The hours between eleven at night and six in the morning were the decreed Scantling time for sleeping, and the streets during that interval were deserted except for the machine security patrols.

It was a half-hour walk, a fine opportunity for the solitary thoughts that summarize today’s work and make plans for tomorrow. I expected to see and hear no one and nothing, except the occasional blinking and electric hum of a mobile monitor camera. With the rising sun in my eyes I did not notice the girl sitting on the stone steps of one of the buildings six blocks from mine, until she moved as I passed.

Objects came rattling down to the sidewalk and rolled under my feet. I, startled out of my reverie, trod on one of them and almost fell. I was still recovering my balance when a dark figure hurried past me and swooped on the rolling sphere.

“Got it,” said a girl’s husky voice. “Did you see where the other one went? Don’t want to lose it.”

In the morning light I saw a gleam of dull red retreating down the slight incline. I took four quick steps forward and picked it up just before it vanished into the open grille of a storm drain.

I looked at what I was holding. It was a glass marble, its swirls of white shot through with blood-red streaks. Before I could do anything else the girl was next to me and had grabbed it from my hand.

“Thanks,” she said. “I wouldn’t have minded losing a glaury or a spumy, but this is an alley-taw blood-orange and I got nothing else like it.”

She spoke with the flat vowels and swallowed consonants of the streets. Her words were gibberish, though I realized that she must be referring to the glass marbles and some children’s game. She went on talking about the little spheres, holding them out to me for inspection. I replied, but I was hardly listening. She was slim and short, no more than an inch or two above five feet. I saw a tangle of black ringlets above a pale, smooth forehead, dark, wide eyes below, a mobile mouth, a clear complexion, and the slender, budding figure of a girl on the brink of adolescence. Her clothes were ugly, too big and too adult for her.

“What are you doing outside at this time of night?” I asked. “You ought to be home in bed.”

My words were, I swear it, spoken in all innocence, and with nothing but the girl’s safety and welfare in mind.

” Tisn’t night,” she said. The deep, husky voice belied her age, but she couldn’t have been more than fourteen. “It’s light now.”

“You know what I mean. Where do you live?”

“Right here.” She raised one arm to point to the building behind her. The overlarge sleeve of her black blouse hung down like a bat’s wing. “Third floor.”

I had entered the building briefly eight months earlier when searching for a place to live. It was, like the tenement where my apartment was located, one of the few structures of central Atlanta not controlled and occupied by Scantlings. Even though it was closer to the institute, I had rejected the place because it seemed populated entirely by transients and smalltime criminals.

“What are you doing out here so early?” I asked.

“That’s my business, not yours.” She stared up at me. “What are you doing out?”

“I’m on my way from work. At the institute.” I pointed west, away from the rising sun.

She nodded, but her mind must have been still on my question to her, because she said, “I come outside because she brought somebody home with her.”

“She?”

I knew the answer, even before she said, “My mother. She brought him last night, about eleven.”

“You had to leave?”

” ’Course not". She frowned at me, as though I had asked a nonsense question. “I live there, don’t I? I could have stayed, even though he was an all-nighter.” She cocked one dark eyebrow at me. “There’d be nothing new, you know. I’ve seen it all before.”

In conventional tests of knowledge and speed of comprehension, I am not boasting when I say that I score well outside the range where such measurements are deemed useful. If I seemed slow to understand what she was saying, it is only that we were beyond my parameters not only of experience but of acceptance.

“Your mother brought a man home to sleep with her last night?” I said.

“Right. Flush, by the sound of him.”

“And you’ve been out here ever since?”

“Oh, no.” She rubbed the blood-orange glass marble against her blouse and peered at it anxiously for damage. “I only come out here a couple of hours ago, when they woke me up. My bed’s right up against the wall and they was making too much noise.” She stared at me and added, apparently in defense of her mother,

“They was both pretty high, I could tell soon as they come in.”

“So when will you go back?”

She pulled a face. “Can go in anytime I want. But I don’t want. Where you going now?”

It was chilly, with a brisk wind swirling around the street corner. I became aware of how hungry I felt. I had eaten nothing since the previous afternoon.

“I’m heading home, for a hot breakfast,” I said. “It’s not far from here. If you don’t want to go home and you would like to eat, you can come with me.”

She took a step closer and looked up at me with eyes too knowing for her age. “Breakfast. That all?”

“It’s all I’m offering.”

“Yeah. Well, okay. Breakfast.”

“Don’t you need to tell your mother?”

“Tell her what? She isn’t invited, is she?”

“No.”

“Anyway, she never eats when she’s working.” She stuffed the marbles into a pocket of the long brown skirt. “Ready when you are.”

“What’s your name?” I asked.

“Paula. Paula Searle.”

“I’m Oliver. Oliver Guest.”

“Pleased to meet you,” she said calmly. The scream or gasp of horror that invariably followed the mention of my name would not occur until five years later. She reached out, her small hand swallowed up in mine for a formal handshake. “You must have a rotten job if it keeps you up all night. What do you do?”

We began to walk side by side, I deliberately shortening my step to fit hers. There seemed little chance that she would comprehend any element of my work, but we had six long blocks to walk. I told her of my own background in biology. I started to explain the nature and causes of apoptosis, the preprogrammed death that comes to most (but not all) cells of an organism. I spoke more for my benefit than hers-my mental review of the previous night’s work had been interrupted by our chance meeting-and I made no attempt to talk down to her or to simplify the intrinsically complex biochemistry.

She said nothing, and after a couple of minutes brought a couple of marbles from her pocket and began to chink them together. I assumed that she had stopped listening, until suddenly she said, “It all happens from inside, don’t it, like the cell’s wearing out? I mean, it’s not like a virus or something gets in and kills it.”