This is such a great and a "meh" book at the same time. The nondual religious perspective will be no surprise to anyone with a background in the practice or study of eastern traditions like Buddhism or Hinduism. I have that background, and I ended up a Jew-by-Choice because at one point my inner sense of a somewhat intercessionary Deity no longer jibed with the God-absent (or at least, intercessionary God-absent) nondual perspective.
From my point of view--which I still hold to be a nondual view, it's entirely possible for everything in the universe--including us--to be part of God. That's the classic nondual perspective that the universe is, basically God's mind and everything and every being is just a solidifying of a small piece God's own conscious awareness. Meaning, we're not the discrete individuals we think we are, but we really all are "echad"--one.
Radical nondualist perspectives like Michaelson's and the more esoteric teachings of Buddhism and Hindusim take that to mean we are absent of any reality, merely the product of external causes and knee-jerk behavioral programming from interacting with other essentially unreal beings. Michaelson finds this a comfort--if everything is God and we don't really exist, then there's no one really to cause or experience pain, and ultimately no one to blame. This can cause a well of compassion for our other, fellow beings to arise, as well as a sense of love for those beings and for God, of which we are all a part.
Michaelson is pretty strident about this. Much like the rock-solid surety about "the way things are" that atheists often profess, Michaelson lays down the law--this is who we are and the way the universe works, and that is that. I always find attitudes like that suspect, and that kind of surety totally undermines Michaelson's arguments for me.
For me, if God is infinite and we are part of God, not only can't we be sure about the nature of God--we can't be sure about the nature of us, either. My sense is that we may be only concretized thoughts of God's, but that we exist that way for a reason, not by accident. There is a thing (a pleasure? a sense of companionship?) experienced by God from reflecting a bit of God-stuff into creating us and letting us think we're separate. It's an easy out to say "we should be good to each other because, how sad, we don't really exist," like Michaelson does. But the other side of that coin is the compassion and love that can flow from supposing that we actually exist for a reason--and maybe we don't know as much as we think we do.
In terms of an easy out, Michaelson's own words betray him here. He labels dual-perspective Judaism (i.e. humans have some reality and God is more than a mere force of nature)a "patronizing allegorization of myth and narrative" (p 143), says that he doesn't "like rules, morals, and oughts," and "can't will [himself] to be compassionate or patient" (p 157.) So much of this book to me seems like Michaelson rationalizing his way around his own personality flaws.
He also misreads Torah while justifying the nondual emotional "ecstasy" that he believes Jewish tradition may really mean by "avodah sh'balev", or service of the heart(p 173). At the time of the writing of the Torah, humans considered thought to reside in the heart, not emotions. This phrase really means intellectual devotion, not emotional devotion, but Michaelson is unaware.
Overall, this is a good introduction to the non-dual perspective. But it's also a closed-minded, overly sure-of-itself take on both Judaism and the nature of God and reality.
My sense is, if given the chance to rewrite this book 10 or 20 years from now, when Michaelson has a better handle on his lack of natural compassion and love for his fellow humans--and perhaps works on those issues in more ways than just meditation retreats, he might write it a bit less self-servingly.