This was the 1977 Hugo award winner for best novel.
It is a near-future apocalyptic tale with some aspects that are disturbingly familiar today (e.g. pollution, climate change, new diseases, genetic engineering).
The writing style is quite different from most of the classic SF authors, with much focus on characters and their emotions. I found it somewhat reminiscent of John Wyndham's work.
An enjoyable novel, unpredictable and disturbing at times, I think it was well deserving of the award
