Fascinating...
The main idea of this book (and the one that interested me the most) is the idea that you are not one self, you are two selves. There is the Eidolon (your normal waking consciousness) and there is the Daemon (what this exactly is not certain but it could be a non-temporal part of you). The Eidolon is the limited self which has all these experiences. The Daemon is the "higher" self (though that term can be misleading) that exists beyond time and space(as the Eidolon would understand it).
This is a groundbreaking book. There are lots of things that happen in life (in your life), that people cannot explain and scientists write them off as hallucination or just anecdotal evidence or claim the witness is just wrong. Science doesnt like the subjective, the *individual* you see. At the moment Science is trying to explain OBEs & NDEs in terms of their Objective Truth. That is, its worth and value is only applicable if it can be shown objectively. (ie the experience you are having is not of value unless that individual experience can be shown to have objective value. Do you notice the problem with that line of argument? I do) But anyway i'm getting sidetracked..my apologies.
What i like about this book is that the author doesnt fall into that same trap. He uses Logic and treats the authenticity of the Subject with respect. According to objective science you will die, your body will decompose and you will be no more. However science does not address the subjective. You live your life through your own subjective experiences. You dont live it from an objective perspective. Suffice to say...something very interesting will probably happen when you come face to death with your "physical" death.
I'm just an average person yet i have had unusual experiences including deja vu moments where i was convinced that X event had happened before. I have experienced a NDE event and i can assure you it was not a "hallucination" unless of course hallucinations are defined as feeling more Real than reality...and there was also very strange kind of pain..not Body/physical pain but pain that felt like i was being forced OUT of my body but i digress! Jung talks a lot about these strange coincidence "events" as synchronicities have a look at his work to find out more. Many great thinkers and scientists have had Eureka moments where a solution would suddenly come to them as if from nowhere... There are parts to consciousness that we currently have barely begun to research. Why is it we have two parts to the brain which each can actually exist independently of the other? And can even seem to be 2 individual consciousness. (google temporal lobe epilepsy also see http://www.bbc.co.uk/science/horizon/2003/godonbrain.shtml).
Another book i would recommend is: The Origin of Consciouness in the Breakdown of the Bicameral Mind by Julian Jaynes....here is as quote from a review of it "His theory, in simplest terms, is that until about 3000 years ago, all of humankind basically heard voices. The voices were actually coming from the other side of the brain, but because the two hemispheres were not in communication the way they are now for most of us, the voices seemed to be coming from outside. The seemed, in fact, to be coming from God or the gods." Very interesting tracking the evolution of the brain and humankind.
Essentially we dont die: upon the moment of death we find that our experience of time is radically changed (elongated to exponential lengths (infinite?)) e.g. people have reported experiencing their entire life as a life review in NDE's. How is this possible? So when the moment of our death actually happens, in physical terms. The significance of that will not matter that much because our awareness seems to exist in an altered temporal or non-temporal state. In other words time slows down immeasurably so and strange things begin to happen...very strange things...
Hopefully this review was a bit helpful in parts at least. The other reviews have done well summarizing the book.