I have, it was recommended to me by a lovely lady whom I enjoy discourse with upon occasion.

Some concepts presented in it resonated with me, things I had pondered in another form but explained in the way it was in Codex seemed to make sense, if not validate my thoughts regarding some energy activity.

In particular the idea that there are those that can take on energy of others and even transmute it from one form/frequency to another.
Unfortunately this is a fact that some people seek to abuse and without consent throw the worst of their energy at another, considering them nothing more than a recycling bin.

Scum, really.

I also find it fascinating regarding people who 'learn to feed' hamstringing themselves. Those who are not simply in a natural state of being, but rather set out to learn how to steal energy. Also scum. These seem easily recognizable though, it can be amusing to toy with them, letting them expose themselves over time. They almost always end up lashing out in desperation, eventually their efforts resort to 'anger trolling' in order to get a reaction.

It's like narcissism by choice, until it's too late and they are become alike to junkies.