I really liked this book. Benford did his best to give us a plausible way for the future to contact the past. There are two sets of characters, past (1962) and future (1998). In 1998 the world is a mess, Renfrew happens to be doing his work with tachyons, which happen to travel backwards in time. They just don't interact with any matter, except indium. It turns out back in 1962 Gordon Bernstein was doing an experiment with indium, but he was getting all sorts of noise in his results.

You have the main storyline of the 1998 team trying to contact the past to somehow save the world from ocean bloom, algae that is covering the oceans and killing the aquatic life beneath, and it's growing worse. Then there are the storylines for sets of characters in the two different time frames. We get to see Gordon's mother who doesn't like the fact that he has a non-jewish girlfriend. i.e. he humanizes so that we get to know them and care what happens.

There's more science in there, too. How do we avoid a paradox?

Timescape is worth reading. I wouldn't say make a special trip to the used book store to find it, but if you happen to stumble across it, picking it up would be good.