Nessus, of the Pierson’s Puppeteer alien race, is a coward. Less cowardly than other members of the species though. So it is that this two headed, long necked being is sent to Earth to recruit a team of explorers. Their mission is to visit a solar system light years away, a region through which the Puppeteers seek safe passage, but are too afraid to explore for themselves. It is a solar system where a ribbon shaped ring of immense proportions circles a star.

The assembled crew will include Louis Wu. Wu, a wisecracking homo sapien with a distaste for human interaction, is a very young looking 200 years old. Then there’s Speaker To Animals, of the overgrown humanoid tiger species called the Kzinti, whose pastimes include waging war and eating raw meat. Finally, there’s Teela Brown, a naive but intrepid twenty year old who, through Puppeteer research, is discovered to be one of the luckiest humans on Earth.

Method and speed of travel is first and foremost on the minds of this crew. As the tale progresses, from teleportation transfer booths on Earth, to the magical discs of the Puppeteer planet, to various space vehicles that make light speed travel possible, the shape and modes of transportation used by the team become increasingly bizarre. It is, in fact, the Puppeteer’s promise to hand over the fastest known ship in the galaxy that serves as the impetus for their journey.

And at the heart of this journey is the Ringworld itself. With a climate not unlike Earth, but covering a surface area three million times larger, it is an artificial ecosystem that is also bizarrely natural. Ringworld is meant to represent nothing less than the ultimate feat in planetary engineering. But who/what are the engineers? For these four travelers, that question becomes less pressing than the ensuing revelations about why they were chosen for the mission. Revelations that are at turns sinister, cosmic and comic.

Niven’s description of Ringworld’s scale and physical laws stands as one of the major accomplishments of hard science fiction. As a novel, it sits at the center of a group of stories making up his Known Space Universe. On the surface, Ringworld chronicles the adventures of a group of intergalactic misfits, but as it unfolds elements are revealed as wide ranging as perspectives on non-human sexual orientation, origins of evolution, global warming, inter-species politics, the psionic phenomenon behind luck, religious dogma, and the question gnawing at the heart of all science fiction fans: do aliens have a sense of humor?