Clarke goes for broke, first putting forward an idea that was totally new at the time: a space elevator. For those of you not scientifically inclined, it's basically a long tether connecting a station orbiting the planet, and people could run up and down the cable in cars. Basically it would make spaceflight easier because ships could launch and refuel up there and not have to worry about gravity and escape velocity and it just opens the entire solar system up. These days it's been more commonplace, writers don't even bother centering entire books around it (though Kim Stanley Robinson probably had this book in mind when he had the Martians install an elevator in his Red/Green/Blue Mars book), but back then it was a fairly new idea. And a great one, it's out there but enough so the reader can envision it, the problem with the Ringworld is that I have trouble picturing it within the realms of reality, I just can't, I know it's possible but I just can't do it. Here, it's gloriously real and Clarke takes you every step of the way. He sets the novel in a renamed Sri Lanka and then proceeds to play with the history, framing the story about a king who built a series of gardens to reach the gods two thousand years before. Also there's this alien spacecraft that happens to pass through years before and laughs at the thought of God, which I thought had little relevance (I thought Clarke was just making sly references to Rendevous with Rama at first) and that makes perfect sense as well. It's a quick read, but not a light one, the science concepts are presented so that those without engineer's degrees can follow. But if you ever thought that we're reached the limits of our technical achievements, go read this and see just how far we can go.