New Theory of Numerology

"Thanks for the book, Harry! I've been wanting that New Theory of Numerology for ages!"

- Hermione Granger to Harry Potter.

New Theory of Numerology, by Lukas Karuzos, is a book that seems to be about Arithmancy, but is not a required text for the subject at Hogwarts School of Witchcraft and Wizardry. Harry Potter gave a copy to Hermione Granger for Christmas in 1995.

Appearances

 * Harry Potter and the Order of the Phoenix
 * Harry Potter and the Half-Blood Prince (film)
 * Harry Potter Limited Edition