Mysterium Magnum is Latin for "great mystery" and has many different associations and usages.
Jacob Boehme (1575–November 17, 1624) a German Christian mystic wrote a treatise entitled, "The Mysterium Magnum" (1623).
Paracelsus and other alchemists employed the term "Mysterium Magnum" to denote primordial undifferentiated matter, from which all the Classical Elements sprang, sometimes compared with Brahman, aether and akasha.
Keely
"This operation of the outflown word becoming a passive substance is the Mysterium Magnum - the greatest hidden secret;" contending that the original of all things lies in that our ideas produce acts; that the Infinite One or the "Word of God" produced creatures. "The Magia is above nature and maketh nature according to its will." [The Action of Force is Spiro-Vortex]
See Also