Timescape is both a fascinating, hard SF book about sending messages backwards through time to save the world and a dull soap opera. The premise is that the world is on the brink of total ecological disaster in 1998, because of the overuse of pesticides. Scientists have discovered how to use tachyons to send a message to the past, with a warning and pointers on how to avoid the catastrophe. The messages are received by a lone scientist in 1963.
The SF portions of the book are really well-done. There are tons of scientific explanations of the tachyons, time paradoxes, etc., which I found mostly fascinating. A bit above my head at times, but fascinating. And the inside look at academia, research, and funding was way more interesting to read than I thought it would be.
However... Much of the book is taken up with the personal lives of the scientists involved. This is where the dull soap opera comes in. For the most part, these characters just aren't leading terribly interested lives, but they're treated as though they are. The lovingly detailed scene of the 1963 scientist walking in on his girlfriend in the bathroom, for example. Most of the characters are thoroughly unlikeable on top of that, especially the womanizing Peterson.
Which brings me to the part women play in the book. They are sexual conquests, housewives, and helpers to men. There are a few female scientists, but they aren't allowed to actually do anything on the page. This is somewhat understandable in 1963, far less so in 1998. I'd even give that a bit of a pass as a product of its time, but this book was written in 1980, not 1960.
One last thing. The messages being sent back in time are meant to give scientists a head start on the pesticide problem. What they actually do is prevent the Kennedy assassination. The chain of events here is more than a little forced, and it's never actually explained why that made a difference.