- "All you will ever need to know about what makes spells work."
- —Flourish and Blotts[src]
Magical Theory was a textbook by renowned author and magician Adalbert Waffling regarding theories of magic, and in particular the essence of spellwork. The book was necessary for first-year students at Hogwarts School of Witchcraft and Wizardry.
A copy of this book could be purchased at Flourish and Blotts in Diagon Alley for two Galleons.