- "All you will ever need to know about what makes spells work."
- —Advert at Flourish and Blotts[src]
Magical Theory written by Adalbert Waffling is a required textbook for first year at Hogwarts. It is available at the Hogwarts Library, or for sale at Flourish and Blotts bookstore for two Galleons.
In a chapter speaking of the first fundamental law of magic:
Tamper with the deepest mysteries - the source of life, the essence of self - only if prepared for consequences of the most extreme an dangerous kind.
During the 1991-1992 school year, a Gryffindor student lost her/his copy of Magical Theory on the Hogwarts grounds and posted a notice requesting its return on the Gryffindor pasteboard. Harry Potter found it near Hagrid's Hut and returned it to the student, receiving a Chocolate Frog Card depicting Mopsus for his trouble.
Hermione Granger owns it, usually storing it in her school trunk.
Behind the scenes
- In the first film, the book´s cover is red. In the video game, it is greenish yellow. In Pottermore, it is blueish-grey.
- At Durmstrang Institute Магичен Теория is a required textbook. Магичен Теория is an incorrect Bulgarian translation of Magical Theory. Durmstrang students could be seen carrying this book during the Triwizard Tournament in the 1994–1995 school year.
- Harry Potter and the Philosopher's Stone (First appearance)
- Harry Potter and the Philosopher's Stone (film)
- Harry Potter and the Philosopher's Stone (video game) (PS2 version)