If one abiding truth about old age never seemed to change, it was insomnia. Sleep was like an old friend who often forgot to visit, or a grandchild who dropped by rarely, only to flee again, leaving you wide-eyed and alone at night.

He could manage a few steps without help, and so Hari did not bother summoning Kers as he shuffled on frail stick-legs from bed to his desk. The suspensor chair accepted him, adjusting sensuously.In a civilization that creaks with age, some technologies still thrive, he pondered gratefully.

Unfortunately, sleeplessness was not the same thing as alertness. So, for some time he just sat there, thoughts drifting back to the other end of his life, remembering.

There had been a teacher once…at the boarding school on Helicon…back when his mathematical genius was beginning to stretch its wings. Seven decades later, he still recalled her unwavering kindness. Something reliable and steady during a childhood that had rocked with sudden traumas and petty oppressions.People can be predictable, she had taught young Hari.If you work out their needs and desires. Under her guidance, logic became his foundation, his support against a universe filled with uncertainty.If you understand the forces that drive people, you will never be taken by surprise.

That teacher had been dark, plump, and matronly. Yet, for some reason she merged in recollection with the other important love of his life-Dors.

Sleek and tall. Skin like kyrt-silk, even when she had to “age” outwardly in order to keep up public appearances as his wife. Always ready with hearty laughter, and yet defending his creative time as if it were more precious than diamonds. Guarding his happiness more fiercely than her own life.

Hari’s fingers stretched, out of habit, starting to reach for her hand. It had always been there. Always…

He sighed, letting both arms sag onto his lap.Well, how many men get to have a wife who was designed from scratch, just for him? Knowing that he had been luckier than multitudes helped take away some of the sting of loneliness. A little.

There had been a promise. He would see her again. Or was that just something he had dreamed?

Finally, Hari had enough of self-pity. Work. That would be the best balm. His subconscious must have been busy during this evening’s brief slumber. He could tell because somethingitched just beneath his scalp, in a place that only mathematics had ever been able to reach. Perhaps it had to do with that clever lichen-artwork in the gardens today.

“Display on,” he said, and watched the computer spread a gorgeous panorama across one side of the room.

The galaxy

“Ah,” he said. He must have been working on the techflow problem before going to bed-a nagging little detail that the Plan still lacked, having to do with which zones and stellar clusters might keep residual scientific capabilities during the coming dark age, after the empire fell. These locales might become trouble spots when the Foundation’s expansion approached the galactic midpoint.

Of course, that’s more than five hundred years from now. Wanda and Stettin and the Fifty think our plan will still be operational by then, but I don’t.

Hari rubbed his eyes and leaned a little forward, tracing patterns that only roughly followed the arcs of well-known spiral arms. This particular image seemedwrong somehow. Familiar, and yet…

With a gasp, he suddenly remembered. This wasn’t the tech-flow problem! Before going to bed, he had slipped in the data wafer given him by the little bureaucrat, that Antic fellow, intending to make a comment or two before sending it back with a note of encouragement.

Probably give him the thrill of his life,Hari had thought, just before his chin fell to his chest. He vaguely recalled Kers putting him to bed after that.

Now he stared again at the display, scanning the indicated flow patterns and symbolic references. The closer he looked, the more he realized two things.

First, Horis Antic was no undiscovered savant. The math was pedestrian, and most of it blatantly cribbed from a few popularized accounts of Hari’s early work.

Second, the patterns were eerily like something he had seen just the other day

“Computer!” he shouted. “Call up the galaxy-wide chart of chaos worlds!”

Next to Antic’s simplistic model, there suddenly appeared a vastly more sophisticated rendering. A depiction that showed the location and intensity of dangerous social disruptions during the last couple of centuries. Chaos outbreaks used to be rare, back in the old days of the empire. But in recent generations they had been growing ever more severe. The so-called Seldon Law, enacted during his tenure as First Minister, helped keep the lid on things for a while, maintaining galaxy-wide peace. But increasing numbers of chaos worlds offered just one more symptom that civilization could no longer hold. Things were falling apart.

Habitually, his eyes touched several past disasters of particular note.

Sark,where conceited “experts” once revived the Joan and Voltaire sims from an ancient, half-burned archive, bragging about the wonders that their brave new society would reveal…until it collapsed around them.

Madder Loss,whose prideful flare threatened to ignite chaos across the entire galaxy, before it abruptly sputtered out.

And Santanni…where Raych died, amid riots, rebellion, and horrid violence.

With a dry mouth, Hari ordered-

Superimpose both of these displays. Do a simple correlative enhancement, type six. Show commonalities.”

The two images moved toward each other, merging and transforming as the computer measured and emphasized similarities. In moments, the verdict could be seen in symbols, swirling around the galactic wheel.

A fifteen percent causation-correlation…between the appearance of chaos worlds and…and….

Hari blinked. He could not even remember what silliness the bureaucrat had been jabbering about. Something about molecules in space? Different kinds ofdirt?

He almost shouted for an immediate visiphone link, to wake Horis Antic, partly in revenge for ruining Hari’s own sleep.

Gripping the arms of his chair, he reconsidered, remembering what Dors had taught him when they lived together as husband and wife.

“Don’t blurt the first thing that comes to mind, Hari. Nor always go charging ahead. Those traits may have served males well, back when they roamed some jungle, like primitive pans. But you are an imperial professor! Always fool them into thinking you’re dignified.“

“When in fact I’m-”

“A great big ape!“ Dors had laughed, rubbing against him. “ Myape. Mywonderful human. “

With that poignant memory, he recovered some calm. Enough to wait a while for answers.

At least until morning.