I Make Myself Invisible in Articles by Aleister Crowley.

“It was at the direction of the head of the Order that I then went to Scotland, to my manor house of Boleskine, which is two or three miles from the Falls of Foyers.

My subsidiary object—the principal aim is too sacred to discuss—put into simple language was to gain control over the ‘four great princes’ of the evil of the world.” [via, also]