Karl von Eckartshausen (German: [ˈɛkaʀtsˌhaʊzən]; 28 June 1752 – 12 May 1803) was a German Catholic mystic, author, and philosopher.
Born in Haimhausen, Bavaria, Eckartshausen studied philosophy and Bavarian civil law in Munich and Ingolstadt. He was the author of The Cloud upon the Sanctuary (de:Die Wolke über dem Heiligtum), a work of Christian mysticism which was later taken up by occultists. The book was given a high status in the Hermetic Order of the Golden Dawn, particularly by Arthur Edward Waite. It is known to have attracted English author and the founder of Thelema, Aleister Crowley, to the Order. Eckartshausen later joined the order of the Illuminati founded by Adam Weishaupt, but "withdrew his membership soon after discovering that this order only recognized enlightenment through human reason."
Von Eckartshausen was acquainted with Johann Georg Schröpfer, an early pioneer of phantasmagoria, and himself experimented with the use of magic lanterns to create "ghost projections" in front of an audience of four or five people. He died in Munich at the age of 50.