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 1970 Nebula Award for Best Novel, and the 1972 Ditmars, an Australian award for Best International Science Fiction.

Fleet of Worlds takes a closer look at Human-Puppeteer (Citizen) relations and the events leading up to Niven's first Ringworld novel. Kirsten Quinn-Kovacks is among the best and brightest of her people. She gratefully serves the gentle race that rescued her ancestors from a dying starship, gave them a world, and nurtures them still. If only the Citizens knew where Kirsten's people came from.

Nothing quite prepared telepath Larry Greenberg for mind-to-mind contact with an alien. In the interest of science, Larry tapped the mind of Kzanol - and that was his first mistake. Kzanol was a thrint from a distant galaxy. He had been trapped on Earth in a time-stasis field for two billion years. Now he was on the loose, and Larry knew everything he was thinking. Thrints lived to plunder and enslave lesser planets - and what the planet Kzanol had in mind was Earth!

The Mote In God's Eye is their acknowledged masterpiece, an epic novel of mankind's first encounter with alien life that transcends the genre. No lesser an authority than Robert A. Heinlein called it "possibly the finest science fiction novel I have ever read".

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.

On the world called Hyperion, beyond the law of the Hegemony of Man, there waits the creature called the Shrike. There are those who worship it. There are those who fear it. And there are those who have vowed to destroy it. In the Valley of the Time Tombs, where huge, brooding structures move backward through time, the Shrike waits for them all.

John Perry did two things on his 75th birthday. First he visited his wife's grave. Then he joined the army. The good news is that humanity finally made it into interstellar space. The bad news is that planets fit to live on are scarce—and alien races willing to fight us for them are common. So: we fight. To defend Earth, and to stake our own claim to planetary real estate. Far from Earth, the war has been going on for decades: brutal, bloody, unyielding. Earth itself is a backwater.

Nine hundred thousand years ago, something annihilated the Amarantin civilization just as it was on the verge of discovering space flight. Now one scientist, Dan Sylveste, will stop at nothing to solve the Amarantin riddle before ancient history repeats itself. With no other resources at his disposal, Sylveste forges a dangerous alliance with the cyborg crew of the starship Nostalgia for Infinity. But as he closes in on the secret, a killer closes in on him because the Amarantin were destroyed for a reason.

At last, one of the world’s greatest works of science fiction is available - just as author Stanislaw Lem intended it. To mark the 50th anniversary of the publication of Solaris, Audible, in cooperation with the Lem Estate, has commissioned a brand-new translation - complete for the first time, and the first ever directly from the original Polish to English. Beautifully narrated by Alessandro Juliani ( Battlestar Galactica), Lem’s provocative novel comes alive for a new generation.

In this prequel to Eon, Greg Bear continues to explore the possibilities presented by the asteroid Thistledown, a remnant of a lost human civilization. The Way is a tunnel through space and time that leads to other worlds, some more like planet Earth than Earth itself. It is perhaps the most formidable discovery in Thistledown and with it come disputes as to the nature of the Way and how it should be used. The Way can be reached only through Axis City, the only space station of Thistledown.