There is quite a lot of interest in
NDEs in the psychological and neuro-biological field and they have naturalistic explanations for NDEs that point towards stress, chemicals or partially functioning of the brain after clinical death as causes. Every systematic and scientific study I have seen on NDEs finds biological causes that can explain all the symptoms.
As many know, there are also a lot of spiritual explanations for NDEs and a lot of books have been written about it. A famous example is the Dutch cardiologist
Pim van Lommel, who has written a book about the phenomenon. He claims that biological explanations cannot explain all symptoms of NDE that he has encountered. The book is a best seller here in the Netherlands (
now translated into english) and when I found out that my sister in law was also reading it, I've also looked at it. I was actually shocked how unscientific the book was, as you would expect a cardiologist to have some scientific background. However, the 'proof' of the spiritual side of NDEs was based on anecdotal evidence. In other words, he had scientifically unverified stories from people that experienced NDEs that were "not explainable by science". 'Of course', he believes these people as 'they had no reason to lie'. Never mind their traumatic life threatening experience and that their mind might have filled in the blanks afterwards.
He also has a whole chapter complaining about science, claiming that "science doesn't know everything", "science has no hart, because it is very clinical and refutes the personal experiences of people", "science has just theories", "the most successful scientist of the past like Galileo were also not excepted by their peers", and so on. And then the worst part of the book starts, his own made up explanation. Here he ties pseudo-scientific explanations of quantum mechanics, entanglement, non-local awareness, holographic universe principle, and ties them all together to a scientific sounding turd.
Maybe other good scientific books about NDE exist that conclude a spiritual cause, but I highly doubt it. The one that I tried to read, and was famous for being scientific, was all but that and horrifically written.