It may be defined as any event in nature which is brought to pass by Will. We must not exclude potato-growing or banking from our definition. Let us take a very simple example of a Magical Act: that of a man blowing his nose.

Some in the Neopagan and occult communities have amended this definition, using the word "magick" exclusively in a paranormal sense. However, Crowley still wields significant influence in these circles.

Concentration or meditation plays an important role in Crowley's system. A certain amount of restricting the mind to some imagined object, according to this theory, produces mystical attainment or "an occurrence in the brain characterized essentially by the uniting of subject and object". (Book Four, Part 1: Mysticism.)

Magick, as defined previously, seeks to aid concentration by constantly recalling the attention to the chosen object (or Will), thereby producing said attainment. For example, if one wishes to concentrate on a god, one might memorize a system of correspondences (perhaps chosen arbitrarily, as this would not affect its usefulness for mystical purposes) and then make every object that one sees "correspond" to said god.

Aleister Crowley wrote:
Now what is all this but to do in a partial (and if I may say so, romantic) way what the Yogi does in his more scientifically complete yet more austerely difficult methods? And here the advantage of Magick is that the process of initiation is spontaneous and, so to speak, automatic. You may begin in the most modest way with the evocation of some simple elemental spirit; but in the course of the operation you are compelled, in order to attain success, to deal with higher entities. Your ambition grows, like every other organism, by what it feeds on. You are very soon led to the Great Work itself; you are led to aspire to the Knowledge and Conversation of the Holy Guardian Angel, and this ambition in turn arouses automatically further difficulties the conquest of which confers new powers. In the Book of the Thirty Aethyrs, commonly called "The Vision and the Voice", it becomes progressively difficult to penetrate each Aethyr. In fact, the penetration was only attained by the initiations which were conferred by the Angel of each Aethyr in its turn. There was this further identification with Yoga practices recorded in this book. At times the concentration necessary to dwell in the Aethyr became so intense that definitely Samadhic results were obtained. We see then that the exaltation of the mind by means of magical practices leads (as one may say, in spite of itself) to the same results as occur in straightforward Yoga. --(Crowley, Yoga for Yellowbellies)

Crowley also made claims for the paranormal effects of magick. However, he defined any attempt to use this power for a purpose other than aiding attainment as "black magic". See Magick of Aleister Crowley by Lon Milo Duquette.

Although Crowley did influence much of what is thought to be magick today, it is constantly being shaped by others in the culture.