Larry Niven and Jerry Pournelle, award-winning authors of such best sellers as Footfall and The Legacy of Heorot, return us to the Mote, and to the universe of Kevin Renner and Horace Bury, of Rod Blaine and Sally Fowler. There, 25 years have passed since humanity quarantined the mysterious aliens known as Moties within the confines of their own solar system. They have spent a quarter century analyzing and agonizing over the deadly threat posed by the only aliens mankind has ever encountered - a race divided into distinct biological forms, each serving a different function: Master, Mediator, Engineer, Warrior.

Welcome to Ringworld, an intermediate step between Dyson Spheres and planets. The gravitational force created by a rotation on its axis of 770 miles per second means no need for a roof. Walls 1,000 miles high at each rim will let in the sun and prevent much air from escaping. Larry Niven's novel Ringworld is the winner of the 1970 Hugo Award for Best Novel.

The planet Quinta is pocked by ugly mounds and covered by a spiderweb-like network. It is a kingdom of phantoms and of a beauty afflicted by madness. In stark contrast, the crew of the spaceship Hermes represents a knowledge-seeking Earth. As they approach Quinta, a dark poetry takes over and leads them into a nightmare of misunderstanding.

At first, only a few things are known about the celestial object that astronomers dub Rama. It is huge, weighing more than ten trillion tons. And it is hurtling through the solar system at inconceivable speed. Then a space probe confirms the unthinkable: Rama is no natural object. It is, incredibly, an interstellar spacecraft. Space explorers and planet-bound scientists alike prepare for mankind's first encounter with alien intelligence.

The gigantic comet had slammed into Earth, forging earthquakes a thousand times too powerful to measure on the Richter scale, tidal waves thousands of feet high. Cities were turned into oceans; oceans turned into steam. It was the beginning of a new Ice Age and the end of civilization. But for the terrified men and women chance had saved, it was also the dawn of a new struggle for survival--a struggle more dangerous and challenging than any they had ever known....