To house the dying Earth's inhabitants, a huge architectural ring is constructed in outer space. With gravity, an atmosphere, and a temperate climate, Ringworld gives humanity a new lease on life, but not without frightening consequences.

"Since fleeing the supernova chain reaction at the galactic core, the cowardly Puppeteers of the Fleet of Worlds have--just barely--survived one crisis after another. The rebellion of their human slaves. The relentless questing of the species of Known Space. The spectacular rise of the starfish-like Gw'oth. The onslaught of the genocidal Pak. Now fresh disaster looms, as though past crises have returned and converged. Who can possibly save the Fleet...

Winner of both the Hugo and Nebula Awards for Best Novel, Ringworld remains a favorite among science fiction readers.

The artifact is a vast circular ribbon of matter, some 180 million miles across, with a sun at its center. Pierson's puppeteers—strange, three-legged, two-headed aliens—discovered this "Ringworld" in a hitherto unexplored part of the galaxy. Curious about the immense structure, but frightened by the prospect of

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