As promoted through his recorder and ghost writer Soror Virakam, this was the preferred brand of occultism sported by the author and failed mystic Aleister Crowley, whose collected works of poetic and proseic form became the focus of study for his numerous fans. The larger explanation for his Magick was contained in Liber ABA, Book Four: Magick, and Part Three of this treatise, aka Magick in Theory and Practice (MiTaP), gleaned Crowley a cult following. Crowley's several definitions or descriptions of his occultism have been eclipsed by his concise language that: "Magick is the Science and Art of causing Change to occur in conformity with Will" though this one of his was one of a number of comparable expressions with which he would compete by reviving this archaic spelling "in order to distinguish the Science of the Magi from all its counterfeits."
Modern publishing and internet communications have glorified or enshrouded substantially the significance of the term's spelling, primarily so as to distinguish occult pursuits from prestidigitation, legerdemain, and stage magic of illusion.
Crowley's followers themselves will sometimes attempt to subsume all sorcery to Magick, despite the fact that their master plainly indicated distinctions of category between 'White Magick' (by which he meant to indicate that which had the specific mystical aim of the Knowledge and Conversation of the Holy Guardian Angel as he picked it up from The Sacred Magic of Abramelin the Mage) and 'black magic' (to which he relegated all other pursuits and considered it of dubious worth without this mystical character).
In his MiTaP, he explains that certain consistent components of Magick are necessary, including the three portions of The Magical Link.