The Earth moves out of some kind of force field, and suddenly, all electromagnetic and -chemical processes; not only do intruments go out of wack, everyone and everything with a brain triples in intelligence. For some individuals, this is liberating, albeit terrifying; some crack under the strain of such a jump. The human race as a whole, indeed, finds itself wondering what wo do with itself. This is a pretty good piece of speculative fiction, the idea taken to the limit. There are great bits, like intelligent chimps rising elephants and teming with African tribes; the story of Brock, the one-time moron, is particularly resonant. Overall, it's certainly a supremely optimistic view. As one character in the book notes, just because people are smart doesn't stop them from doing stupid things like speeding or smoking; nor does intelligence always erase prejudice. Yet Anderson envisions a human race that, due solely to higher intelligence, (after a lengthy period of great strife) transcends war, patriotism, and borders - indeed, seems at the end to have formed into some unified collective mind. I'm not so sure that all this necessarily follows from increased intelligence, even such an exponential leap in brain activity; but I see that Anderson is actually painting humans as the wise celestial visitors that most SF authors depict alien beings as. It's sort of a nice touch. Recommended.