Cosmology
The fictional universe in which the books are set has its own cosmology, in which the normal material world is only the lowest level. Above the physical world, there are numerous metaphysical planes. Although planes are technically collections of supernatural forces, the text of the books usually describes these higher planes as if they were regions of spacetime—albeit with vastly different natural laws.
The etheric plane, which is described as being directly "above" the material world, is associated with the five classical elements used in the novels—earth, air, fire, water, and aether. The astral plane, which is described as being "above" or "within" the etheric plane, can be tapped by characters as a source of magical energy. The glossaries at the end of the books also equate it with the Akashic Record.
Numerous other planes have been briefly mentioned, such as the Green Lands, the Orange Lands, Earth of Earth, and the Land of Husks and Rinds. However, their properties or arrangement are not detailed.
Read more about this topic: Dweomer (Deverry Cycle)