Can Superman make a baby with Lois Lane, or is he doomed to be the last of his kind? This article discusses the scientific and medical issues involved in copulating with a Kryptonian. Also includes "Unfinished Story No. 1" and "Unfinished Story No. 2".

This nonfiction essay, first published in Galaxy in March 1969, discusses the many uses, implications, and limits of teleportation, from personal transportation to interstellar travel.

This nonfiction essay, first published in Vertex in April 1973, discusses the grandfather paradox.

Aros of Azteca and Neoloth-Pteor are the deadliest of enemies: swordsman and sorcerer, locked in mortal combat, who have tried to kill each other more times than either can count. But when the princess Neoloth loves is kidnapped, there is only one plan that offers any hope of rescue...and that requires passing off the barbarian Aros as a lost princeling and infiltrating the deadliest cabal of necromancers the world has ever seen. They cannot trust each other. They will betray or kill each other the first chance they get. But they're all each other has.

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".

They first appear as a series of dots on astronomical plates, heading from Saturn directly toward Earth. Since the ringed planet carries no life, scientists deduce the mysterious ship to be a visitor from another star. The world's frantic efforts to signal the aliens go unanswered. The first contact is hostile: the invaders blast a Soviet space station, seize the survivors, and then destroy every dam and installation on Earth with a hail of asteriods.

Best-selling science fiction superstars Larry Niven and Jerry Pournelle combine their talents with those of Steven Barnes in an extraordinary adventure of humankind’s first outpost in the farthest reaches of space. Light years from Earth, colonists land on a planet they name Avalon. It seems like a paradise—until native creatures savagely attack. It will take every bit of intelligence, courage, and military-style discipline to survive.

They mustn't harm a human being, they must obey human orders, and they must protect their own existence...but only so long as that doesn't violate rules one and two. With these Three Laws of Robotics, humanity embarked on a bold new era of evolution that would open up enormous possibilities, and unforeseen risks.

It was January 2021, and Rick Deckard had a license to kill. Somewhere among the hordes of humans out there lurked several rogue androids. Deckard's assignment: find them and then..."retire" them. Trouble was, the androids all looked exactly like humans, and they didn't want to be found!

What’s to be done about a jaywalking moose? A bear caught breaking and entering? A murderous tree? Three hundred years ago, animals that broke the law would be assigned legal representation and put on trial. These days, as New York Times best-selling author Mary Roach discovers, the answers are best found not in jurisprudence but in science: the curious science of human-wildlife conflict, a discipline at the crossroads of human behavior and wildlife biology.

Ryland Grace is the sole survivor on a desperate, last-chance mission - and if he fails, humanity and the Earth itself will perish. Except that right now, he doesn't know that. He can't even remember his own name, let alone the nature of his assignment or how to complete it. All he knows is that he's been asleep for a very, very long time. And he's just been awakened to find himself millions of miles from home, with nothing but two corpses for company.

It’s 1984, and life has changed beyond recognition. Airstrip One, formerly known as Great Britain, is a place where Big Brother is always watching, and nobody can hide. Except, perhaps, for Winston Smith. Whilst working at the Ministry of Truth, rewriting history, he secretly dreams of freedom. And in a world where love and sex are forbidden, where it’s hard to distinguish between friend and foe, he meets Julia and O’Brien and vows to rebel.

Six days ago, astronaut Mark Watney became one of the first people to walk on Mars. Now, he's sure he'll be the first person to die there. After a dust storm nearly kills him and forces his crew to evacuate while thinking him dead, Mark finds himself stranded and completely alone with no way to even signal Earth that he’s alive - and even if he could get word out, his supplies would be gone long before a rescue could arrive. But Mark isn't ready to give up yet.

Inheriting your uncle's supervillain business is more complicated than you might think. Particularly when you discover who's running the place. Charlie's life is going nowhere fast. A divorced substitute teacher living with his cat in a house his siblings want to sell, all he wants is to open a pub downtown, if only the bank will approve his loan. Then his long-lost uncle Jake dies and leaves his supervillain business (complete with island volcano lair) to Charlie. But becoming a supervillain isn't all giant laser death rays and lava pits.

Jazz Bashara is a criminal. Well, sort of. Life on Artemis, the first and only city on the moon, is tough if you're not a rich tourist or an eccentric billionaire. So smuggling in the occasional harmless bit of contraband barely counts, right? Not when you've got debts to pay and your job as a porter barely covers the rent. Everything changes when Jazz sees the chance to commit the perfect crime, with a reward too lucrative to turn down.

Nominated for both the Hugo Award and the Nebula Award, this short story introduces the Warlock, who discovers to his horror that the world's mana, the fuel that makes magic work, is rapidly dwindling. The news spells doom for magic-based society. Unfortunately, no secret that powerful can stay hidden for long.

A stranded Rammer who finds himself transported from the depths of space to humanity's cradle on Earth tells his harrowing tale to a people-watcher. This short story was first printed in Galaxy in September 1969.

Like "Cloak of Anarchy", this story is peopled with fictional versions of several of Niven's friends. A discussion among friends about the theory of "Multiple Edens" suddenly becomes all too real, and the reason Tom Findlay has been asking such interesting questions over the years becomes clear.

The tragic story of the first manned expedition to Pluto, and the fate of the surviving astronaut who finds a unique way to prolong his lifespan in hopes of rescue.

Detective-Lieutenant Gene Trimble faces an increasing number of bizarre suicides in a world struggling to come to terms with its place in a multiverse of different timelines, where every decision ever made by anyone becomes an alternate universe.