Monroe's map
Robert Monroe didn't have any formal education of occult matters. He is very independent minded and didn't want to lock himself into any belief system. As such, he mistrusted any "spiritual" teachings.
Thus, when he started experiencing OBEs, he started drawing his own map of the Astral.
He started doing so in his first book, Journeys out of the Body.
One of the most common questions that arises during any discussion of the Second Body and the Second State is: Where do you go? In evaluation of all experiments, there evolved what seemed to be three Second State environments.
The first of these was identified as Locale I, for lack of a better nomenclature. More appropriately, it could be called the "Here-Now." 1
[...]The best introduction to Locale II is to suggest a room with a sign over the door saying, "Please Check All Physical Concepts Here." If getting accustomed to the idea of a Second Body was an uneasy experience, Locale II may be hard to take. It is certain to produce emotional effects as it steps solidly upon what we have accepted as reality. Furthermore, many of our religious doctrines and the interpretations thereof become open to question, 2
[...]Paradoxically, the scientist today can conceive far more easily of the possibility of the area here labeled Locale III than that of Locale II. Why? Because it fits his latest discoveries in physics, small bits of evidence he has uncovered in his experiments with matter bombardment, accelerators, cyclotrons, etc. 3
