James P. Hogan

The man on the moon was dead. They called him Charlie. He had big eyes, abundant body hair, and fairly long nostrils. His skeletal body was found clad in a bright red spacesuit, hidden in a rocky grave....

Eons ago, a gentle race of giants fled the planet Minerva, leaving the ancestors of man to fend for themselves. Fifty thousand years ago, Minerva exploded, hurling its moon into an orbit about Earth....

Long before the world of the Ganymeans blew apart millennia ago, the strange race of giants had already vanished. All that remained of them was a wrecked ship abandoned on a frozen moon of Jupiter....