I have not read the Roth Trilogy, but watched the television adaptation of the books by Andrew Taylor. The technique of going backwards in time as a why-did-it rather than the normal who-dun-it was extremely well done.
We followed Rosie's journey from an adult psychotic mass murderer back through time to a very spoilt jealous teenager, and then back again to a little disturbed 5 year old, who cut the wings off birds. I think one of the real lessons we can learn from the series is the difficulty of dealing with anyone who has no remorse, and is prepared to lie with a straight face. Our society cannot cope with the barefaced psychotic liar, because our police powers and psychiatric services are geared up for the normal person and their "rights".
Will our liberal "don't punish anyone too severely" society breed more murderers?
Will young child murderers such as the killers of Jamie Bulger go on after release to be perfect citizens, or have they been irrevocably compromised by their despicable acts?
The Roth Trilogy left many questions unanswered, or perhaps the answers are not what we want to hear.