The Aethyrs are the last major part of the Enochian material to be received, and they arrive as a complete administrative structure rather than as a description of a place.
Each of the thirty is named by a word of three letters, LIL first and remotest and TEX thirtieth and nearest to the world. Attached to them are ninety one governors, distributed three to each Aethyr with an extra in the first, and each governor is assigned a territory on the earth. The tables setting those assignments out, with the number of ministers under each governor and the region each is said to have charge of, occupy a manuscript of their own, so the system maps a hierarchy of spirits onto a geography of the known world.
Entry is by recitation. A single invocation, delivered in the Enochian language with an English rendering, is used for every Aethyr, with the three letter name of the one being sought substituted at the appropriate point. There is no ascent through the physical world and no correspondence to a sky; the ordering is one of remoteness from ordinary consciousness.
The material came through Edward Kelley, who reported what he saw in a shewstone while John Dee, a mathematician and adviser to the English court, sat beside him writing it down and asking questions. Dee's diaries record the sessions in detail, including his own doubts and the difficulties between the two men, and it is that record, published in the seventeenth century and preserved in manuscript, that later practitioners have worked from.