This book is the follow-up to Touch of Evil by the same authors, and it continues the story of Kate Reilly, her werewolf boyfriend, Tom, and various other characters. The authors' take on the vampire/werewolf mythology is rather different than the norm, the Thrall being a hive mind with which Kate is linked following the events in the previous book.

Touch of Madness starts a month after the end of the previous book, and Kate finds herself once again in the thick of a load of trouble. Some eggs have been stored, and while Kate and the other Not Prey are in a meeting to discuss further studies, the eggs escape. Kate and police detective Brooks do what they must to stop the infestation and find themselves being sued. At the same time, Kate is approached by the vampires to find some other eggs that have been stolen, her relationship with Tom looks like it might have problems because he may be needed to sire more werewolves and Kate is sterile, plus her brother, who is in an almost-zombie state, is proving difficult to handle and may lose his place in the care facility - not to mention two evil and insane women on the run who both have it in for Kate.

There are several threads of plots all overlapping, and that's what makes the book interesting. There are also several different 'baddies' who are after Kate or those whom she loves, as well as the confusion over good and bad with regard to the Thrall. Kate considers them evil parasites, but she's beginning to discover this may not be entirely correct.

The relationship with Tom was well established in the first book, and in this book it continues and deepens. Her relationships with other people, such as her brothers, Joe and Bryan, come under more scrutiny, and we see a lot of heartache among them. Kate does come across like an early Anita Blake, always in the thick of things, internally conflicted about her actions but brave and almost suicidal at the same time. Fortunately the people around her take care of her and seem amazingly supportive - most of the time.

I initially found this book rather difficult to get into, mainly because I hadn't read the previous book in the series. However, after the first couple of chapters I found myself drawn into Kate's world and learning about the events that have made her the person she is. There is an awful lot of backstory from the first book doled out in small portions, and that meant I didn't always understand everything. I found the book very enjoyable nevertheless, and the non-stop action made it an exciting read. The fact that it is written by two people is never apparent as the writing style feels congruent and smooth without the odd jarring notes that twin authorship can sometimes bring. This is an excellent book and exciting, but it is probably worth reading Touch of Evil first so that there is less complicated plot to work out.