“Magic is the science and the art of causing change to occur in conformity with will.”

Introduction.
Magick Book IV : Liber ABA, Part III : Magick in Theory and Practice (1929)
Context: Magick is the Science and Art of causing Change to occur in conformity with Will.
(Illustration: It is my Will to inform the World of certain facts within my knowledge. I therefore take "magical weapons", pen, ink, and paper; I write "incantations" — these sentences — in the "magical language" ie, that which is understood by the people I wish to instruct; I call forth "spirits", such as printers, publishers, booksellers and so forth and constrain them to convey my message to those people. The composition and distribution of this book is thus an act of Magick by which I cause Changes to take place in conformity with my Will.)
In one sense Magick may be defined as the name given to Science by the vulgar.

The Necessity of Art: A Marxist Approach (1965), Penguin Books, translated by Anna Bostock.

Source: The Golden Bough (1890), Chapter 4, Magic and Religion.
Context: From the earliest times man has been engaged in a search for general rules whereby to turn the order of natural phenomena to his own advantage, and in the long search he has scraped together a great hoard of such maxims, some of them golden and some of them mere dross. The true or golden rules constitute the body of applied science which we call the arts; the false are magic.

The Abolition of Man (1943)

Source: Committee of human rights reporters, 2011 http://archive.is/0d2i

As quoted in Ben Shapiro, a Provocative ‘Gladiator,’ Battles to Win Young Conservatives https://www.nytimes.com/2017/11/23/us/ben-shapiro-conservative.html (November 23, 2017) by Sabrina Tavernise, '.

Things That Make Us Smart (1993), Epilogue.

Miscellaneous Quotes On the Subjects of Magic and Magicians
Source: Dogme et Rituel de la Haute Magi Part I: The Doctrine of Transcendental Magic By Eliphas Levi (Alphonse Louis Constant), Translated by A. E. Waite, England, Rider & Company, England, 1896, Introduction p. 11

Source: Stations of the Tide (1991), Chapter 8, “Conversations in the Puzzle Palace” (p. 130)