Peter Brown was relatively unknown, but a truly unique voice in the "spiritual" scene. He didn't follow the typical non dual jargon and concepts you hear from most others. Just a genuine attempt at communicating what can't said.

Here's a couple YT video's if you are interested in listening to his teaching:

https://www.youtube.com/watch?v=7_Ec7OI_p0c

https://www.youtube.com/watch?v=TDaItrO_Pjc

I'll post an email from him I received last year, which really helped put things into perspective:

"It can be easy to have an idea of “finality” or completeness, crossing some line into resolution or everything somehow falling into place, into some resolved whole.

A big part of the learning curve in the later stages of unfoldment is seeing through and letting go of these fantasies of finality and relaxling into the true nature of actuality, which is its infinity, its openhandednes, unresolvability, ambiguity, bottomlessness, etc.

The ambiguity that you’ve always felt has in fact been true all along- there is no final condition beyond this, no “wrapping up” or pulling together into some neat package. Reality is an unresolved/unresolvable paradoxical infinity that presents as an ongoing flow of contradictory implications, perspectives or dimensions of possible ways it “might be”, none of which are any more (or less) accurate than any other-

It itself is mystery, infinity, an unanswered question. This lack of finality IS the true finality; this endlessness is the actual end. Coming to see the self-verifying truth of this is the final realization.

So relaxing into this unresolvability, letting go of these fantasies of completion is the final maturity."

Here's a good summary of his teaching on his website: http://theopendoorway.org/yoga.htm