I was never that into Manson, but picked this up at the store on a whim and found it pretty captivating. Doesn't waste time mythologizing him (nor does O'Neill make any concrete hypotheses), but goes into some incredibly well-researched detail regarding MKUltra and the CIA's interest in using Haight-Ashbury at the peak of hippie culture to perform "field research" in testing the possibility of mind control with combinations of LSD and amphetamines.
There's a lot of irrefutable evidence that Manson was on the radar of the FBI / CIA for a while before the Tate-LaBianca murders and that they seemed to have a vested interest in keeping him on the street despite innumerable parole violations that should have landed him behind bars.
Highly recommended.
This is basically the gist of the book. Not any conclusive endings, but fascinating book all the way.
Yup. I respect O'Neill for being honest about his inability to tie the narrative up with a pretty little bow. He lays it all out there for the reader and lets them make the connections. Like you said, a fascinating read either way.