Hi Nathaniel
It’s Bhante Henepola Gunaratana a Buddhist monk. Here are his books on Amazon: https://www.amazon.com/Bhante-Henepola-Gunaratana/e/B002LADY6O
I believe he is first mentioned on page 1873 of “The Matter With Things.”
I read a few of his books some years back and found him to be a very clear writer but rather doctrinaire in terms of Theravada Buddhism.
I personally think there is at least one other book that is FAR closer to the essence of what Iain is addressing: “The Way of Effortless Living,” by Loch Kelly. Loch works with the non duality laboratory at New York University, and has been a subject in numerous experiments. He studied traditional Theravada Buddhism as well as Dzochen and Mahamudra practices from Tibet, North India and Nepal. He has been “translating” these practices into modern simple forms for over 25 years and his work is VERY very accessible.
Good luck with your search. In any case, the essence of it is very simple:
There is an open, non controlling awareness within which all experience unfolds.
you can learn easily to be aware OF it – it is still, silent, vast spaciousness. But even more simply, imagine a dog. Now erase the image of the dog. What remains? Awareness, spacious, unbounded.
Loch has several dozen brief exercises along these lines. After you become comfortable learning to be aware OF spacious awareness, you will discover – quite spontaneously at some point – you can be aware FROM spacious awareness, and finally, as you “drop into the Heart,” aware AS spacious awareness.
As you abide more and more like this, you will find the entire universe transformed, and all the things Iain tries to write about that we think and analyze or even feel, become viscerally obvious. As more and more people recognize this, science, politics, economics, health care education and all other aspects of human life will be utterly transformed.