One book I like very much is The Myth Of Freedom by Chogyam Trungpa. Of particular interest is the section where he distinguishes the realms of existence as mental states and ways of being.
I've yet to find this discussed elsewhere in any way that resonates. Everything I find merely talks about Buddhism and psychology and speaks about it in terms defined in the latter.
Trungpa nourishes the metaphor and generates a rich unanswerable question. Other writings I've found prey on the metaphor and regurgitate a definitive answer.
The former offers opening for insight; the latter suppresses thought.
Does anyone know of anywhere else this subject is written upon with the type of creativity I've alluded to?