This is book three of the rat trilogy and I recommend reading them in sequence. The whole series is a brutal social commentary about London's governing body. The cover ups, the filth that breeds from negligence, the bad judgement of the establishment and those left to fight for survival. Written over 30 years ago the underlying narrative is as fresh and relative as it was when my parents read it.
The biggest frustration for me is the portrayal of women within the books, as helpless frail and silly, destitute or as baggage being transported with only one women standing out as being slightly self sufficient or educated. A sign of the times from when it was written, Herbert's underlying feelings towards women or another sub context of the social commentary? I'll let you decide.
The rats themselves are scary in their description, the narrative gripping and compelling, but the context of it being set in London (throughout the series) where I have lived made it or the more thought provoking and chilling.
Do not be put off by the sub meanings underlying in the narrative, as the concept of the rats at face value are pretty horrific and terrifying enough.
I recommend this book to horror readers, those who can immerse themselves in apocalyptic survival and individuals who can relate to feeling like a small fish in a big sea of sharks.