This is a book that you will love if you are into abnormal psychology.
Momma is a sociopath: she's narcissistic, selfish, self-absorbed and lacks empathy. She will never admit to doing anything wrong and find a way to justify any- and everything she's ever done. No wonder she raised a serial killer.
It also brings up another question - if you are willing to look deep enough - about serial killers:
Are they created by nature or nurture?
In this case the answer seems obvious and as the reader goes along, we may feel sympathy for the serial killer himself.
But, at times it feels like a he said-she said situation. Since momma is clearly the "bad guy" in this story, the reader may side with the son and disbelieve anything that momma has to say. However, he turned out to be a serial killer, so can we really believe everything he claims?
This story will not be for everyone, the subject matter is of deeply disturbing themes and it doesn't read like your typical story, but for those who "get it", you will love what the author did.