Just so you know, THIS is Vancian magic

Selections from Jack Vance's The Dying Earth.

The tomes which held Turjan's sorcery lay on a long table of black steel or were thrust helter-skelter into shelves. These were volumes compiled by many wizards of the past, untidy folios collected by the Sage, leather-bound librams setting forth the syllables of a hundred powerful spells, so cogent that Turjan's brain could know but four at a time.

Turjan found a musty portfolio, turned the heavy pages to the spell the Sage had shown him, the Call to the Violet Cloud. He stared down at the characters and they burned with an urgent power, pressing off the page as if frantic to leave the dark solitude of the book.

Turjan closed the book, forcing the spell back into oblivion. [...] Then he sat down and from a journal chose the spells he would take with him. What dangers he might meet he could not know, so he selected three spells of general application: the Excellent Prismatic Spray, Phandaal's Mantle of Stealth, and the Spell of the Slow Hour.

Spells are almost alive with power. Memorizing a spell is kinda like putting a demon in your head.

In this fashion did Turjan enter his apprenticeship with Pandelume. Day and far into the opalescent Embelyon night he worked under Pandelume's unseen tutelage. He learned the secret of of renewed youth, many spells of the ancients, and a strange abstract lore that Pandelume termed "Mathematics".

"Within this instrument," said Pandelume, "resides the Universe. Passive in itself and not of sorcery, it elucidates every problem, each phase of existence, all the secrets of time and space. Your spells and runes are built upon its power and codified according to a great underlying mosaic of magic. The design of this mosaic we cannot surmise; our knowledge is didactic, empirical, arbitrary. Phandaal glimpsed the pattern and so was able to formulate many of the spells which bear his name. I have endeavored through the ages to break the clouded glass, but so far my research has failed. He who discovers the pattern will know all of sorcery and be a man powerful beyond comprehension."

So Turjan applied himself to the study and learned many of the simpler routines.

"I find herein a wonderful beauty," he told Pandelume. "This is no science, this is art, where equations fall away to elements like resolving chords, and where always prevails a symmetry either explicit or multiplex, but always of a crystalline serenity."

Magic as hyperdimensional mathematics, similar to Lovecraft's The Dreams in the Witch-House.

The Magician climbed the stairs. Midnight found him in his study, pouring through leather-bound tomes and untidy portfolios... At one time a thousand or more runes, spells, incantations, curses, and sorceries had been known. The reach of Grand Motholam--Ascolais, the Ide of Kauchique, Almery to the South, the Land of the Falling Wall to the East--swarmed with sorcerers of every description, of whom the chief was the Arch-Necromancer Phandaal. A hundred spells Phandaal personally had formulated--though rumor said that demons whispered at gus ear when he wrought magic. Pontecilla the Pious, then ruler of Grand Motholam, put Phandall to torment, and after a terrible night, he killed Phandaal and outlawed sorcery throughout the land. The wizards of Grand Motholam fled like beetles under a strong light; the lore was dispersed and forgotten, until now, at this dim time, with the sun dark, wilderness obscuring Ascolais, and the white city Kaiin half in ruins, only a few more than a hundred spells remained to the knowledge of man. Of these, Mazirian had access to seventy-three, and gradually, by stratagem and negotiation, was securing the others.

Maziriam made a selection from his books and with great effort forced five spells upon his brain: Phandaal's Gyrator, Felojun's Second Hypnotic Spell, The Excellent Prismatic Spray, The Charm of Untiring Nourishment, and the Spell of the Omnipotent Sphere. This accomplished, Maziriam drank wine and retired to his couch.