I read the book before seeing the movie. I thought the movie was EXTREMELY poorly done! I understand Christina Crawford herself refused to see it for that reason. It's sad that Faye Dunaway's career was ruined with this monstrosity.
Christina Crawford has made it her life work to speak out against victims of hidden child abuse. She has written several books. She currently operates a Bed & Breakfast in Northern Idaho, and has released a 30th Anniversary issue of "Mommie Dearest", which includes a Forward section where several of John Crawford's contemporaries speak in defense of Christina, and where she adds several more photographs and pages of her life as an adult.
I haven't been able to get hold of the 30th Anniversary edition, but am currently re-reading the original. I now have new insight as to how victims of child abuse are affected in adulthood, and why they so often pass it on. Christina made up her mind early never to have children; that's how she was able to stop the generational progression with herself.