Yes I read it. I also had a chance to talk to Bryan briefly and then listen to his presentation. Delusions snd sleep paralysis were offered as a possible explanation for the abduction phenomenon.
Look, I don’t know what this is but nothing in that lack of knowledge induces me to jump on what I see as the least likely explanation. I certainly wouldn’t believe anything coming out of this administration. There’s just as much swampy deep state in the military as anywhere else
My reading of Bryan's book led me to surmise that he was as dumbfounded as the rest of us. But be that as it may, Mack eliminated certain possibilities, among them the insanity of the witnesses and delusions (unless you consider a mass delusion wherein all the many unrelated witnesses essentially have the same very unique abduction delusion).
Their conclusion is that something is going on, but no one seems to know what the hell it is.
It is called the "Phenomenon" for lack of a better name.
Here are many experiencers that relate what happened to them.
You can pick and choose who you want to believe.
Start at the oldest podcast first:
https://podbay.fm/p/aliens-and-artists