The diggers called themselves the earth people, making tunnels through the soil and into the trunks of trees they hollowed out. The angels were the sky people, building roofed nests in trees and hanging upside down from limbs to sleep, to argue, and to teach. The humans were the middle people now, living in houses above the ground.

There was no digger city without human houses on the ground above it, no angel village without the walled chambers of the middle people providing artificial caves. The vast knowledge that the humans brought with them from the planet Harmony was only a fraction of what their ancestors had known on Earth before their exile forty million years before. Now even that was mostly lost; yet what remained was so far superior to what the people of the earth and sky had known that wherever the middle people dwelt, they had great power, and usually ruled.

In the sky, however, the computer of the starship Basilica forgot nothing, and through satellites it had deployed around the Earth it watched, it collected data and remembered everything it learned.

Nor was it alone in its watching. For inside it lived a woman who had come to Earth with the first colonists; but then, clothed in the cloak of the starmaster, she returned into the sky, to sleep long years and waken briefly, her body healed and helped by the cloak, so that death, if it could ever come to her at all, was still a far distant visitor. She remembered everything that mattered to her, remembered people who had once lived and now were gone. Birth and life and death, she had seen so much of it that she barely noticed it now. It was all generations to her, seasons in her garden, trees and grass and people rising and falling, rising and falling.

On Earth there was a little bit of memory as well. Two books, written on thin sheets of metal, had been maintained since the return of the humans.