Timescape
by Gregory Benford
  

Simon & Schuster: New York, 1980

One of the problems of trying to write hard science fiction — that is, stories of future scientific discovery — is that you need to have scientists for characters, and you don't know any scientists. Greg Benford knows a lot of scientists, and is a scientist himself: a physics professor at UC Irvine. So his characters ring true. Some of them aren't very likable, some are dull or even stupid, but they all are believable.

Timescape is slow reading (at least it was for me) because there is a wealth of description and thought-provoking ideas in it. Especially detailed are the settings in America and England, in the recent past and near-future (1962 and 1998). If you skip the descriptions you will miss most of the charm of this book.
  

The story goes like this, though a lot less directly: in 1962, Gordon and his student assistant are fooling around with some experiment, and there is interference from tachyons, which are supposed to be faster than light. It looks like a message, either from the stars or from the future. Their superiors scoff, naturally, and nothing is done about it.

Meanwhile, in 1998 (alternating chapters, a la Edgar Rice Burroughs), Renfrew and other scientists are fighting pollution, which has gotten worse. In the past, why didn't they do this, or refrain from doing that? Why not tell them? How?
  

I thought the main premise, that one could change the past somehow, was both flawed and jaded, but the reason for doing so (to forestall pollution) was fresh. The ending is disappointing (also jaded) but then it's not telegraphed, and I'm not going to telegraph it here. Suffice it to say that Timescape made me think, and isn't that what science fiction is all about?