Peter Manson is confronting middle age, and his relationships with all the women around him seem to be an indicator of this: his stay-at-home, comfortable wife Cassie, his new secretary Sarah and, most of all, his recently married and pregnant daughter Prue. In the short time period covered by the novel, everyone's life is overturned and things will never be the same again.
I'm not old enough to remember the infamous TV series but I do remember someone at school sneaking the book in from their mum and us all passing it around as young teens. Re-reading it now, it's far more drawn out and both less sensationalist and less menacing than I remember.
Much is written from inside Peter's head with some of the other scenes focusing on the other characters which makes it feel a little jumpy at times, not quite a smooth and flowing narrative. Published in 1969, this almost feel like an alien world: businessmen still have secretaries to whom they dictate letters; and a woman working is both an option and almost an indulgence.
If you come to this from the 2010 TV series, then prepare for quite a few changes both in setting (Peter is a publisher, not an architect; Gavin is an American student; Cassie hasn't ever worked) as well as in interpretation. Most strikingly, Prue is 19 and at college where she meets Gavin who is more or less the same age, which places their relationship in a very different power dynamic to that in the series where she's still at school and he's her teacher. Prue in the book is far less of a victim and much more complicit in all her relationships (Peter at one point sees her as the puppet-master behind events) which I think makes the story both different and more interesting.
So overall this is a gripping read that still manages to be almost shocking in 2010.