I had a hard time getting past the first half of the book, because it didn't really hold my interest. I felt that the author kept going off on tangents that didn't really need to be there. For instance, she went into great detail about the life of the young boy who found a key piece of evidence. She could have summarized this in one sentence, as the boy's life story was inconsequential to the plot. The second half of the book moved along a lot faster.
I did identify with one major character though, as I have known three women in my family that have very similar personalities. The author tried to give reasons as to why Nicola's personality became so deviant (i.e. the parents always giving in to her, her father being gone a lot, her father playing roles when he was under cover, not being honest about his work, etc.). However, having known female relatives like her that were brought up in larger, morally sound families, I've come to the conclusion that these people are born this way. Having seen a documentary on Borderline Personality Disorder, this mental condition closely relates to my family members. They were like this from early childhood, and just didn't see the world as others did, so had a hard time holding on to any relationships (especially with other females). Just as with Nicola's character, the longest relationships my family members had were with men, because they were able to manipulate them with sex (or just the promise of it). Of course this type of manipulation works best when the female is also very attractive.