Louis Wu is two hundred years old and feels he needs some excitement in his hife. He's approached by Nessus, a "Pierson's Puppeteer", who wants to recruit a crew to investigate a strange phenomenon far on the outskirts of Known Space. With Teela Brown, another human, and Speaker-to-Animals, a Kzin, they all set off and reach what turns out to be "Ringworld": an unimaginably huge ribbon of artificial material that orbits a star.
Lots of great ideas in this book: Niven describes how the Ringworld is configured with "shadow squares" that provide day and night on the surface of the world, and describes how these might be held in place. Like his other books, some of the descriptions are not quite good enough to make clear exactly how things work, but I think he doesn't do too badly here.
It turns out that the "engineers" who built the Ringworld have long gone (there's a follow-on book called The Ringworld Engineers which I may get around to reading) and so quite a bit of the physics is just left unexplained, but there are some interesting bits and pieces, such as the cziltang brone: a mechanism that makes the surface of the world permeable so that spaceships can get their cargo through without needing mechanical airlocks; the tasp which can stimulate the pleasure centre of someone's brain and therefore control them and Teela Brown's "luck".
I think the criticism would be that it all seemed to end very suddenly: it takes around 90% of the book to get to Ringworld, cross countless miles of it on air-scooters and find someone to help them get off it again, and then about ten pages to get all the way back to their spaceship and escape.
I think of this as a sequel to Protector although having re-read the two I don't think that they are particularly interdependent. I also have the feeling that The Ringworld Engineers was a bit of a let-down when I last read it, but I think it could be worth another go.
Completed : 07-May-2007