 Manual of Insight by Mahasi Sayadaw Emptiness: A Practical Guide by Guy Armstrong (good introduction to the Buddhist version of reality) Books by Loch Kelly (practical guide to non-dual meditation practices within Buddhism; The Little Book of Being by Diana Winston may be a better introduction) Seeing that Frees by Rob Burbea (really advanced but profound) http://awakeningtoreality.blogspot.com/0000/00/thusnesss-six-stages-of-experience.html (Buddhism > Advaita