from the Introduction:
Several months ago, I finally broke down and read one of the Harry Potter books. Like everyone else, I became addicted. I quickly read all four books in the series in quick succession and then re-read them. As I read, I kept wondering if J.K. Rowling was a former gamer, because the parameters of her world were so carefully thought out. Underneath the prep school fantasy, there was a tautly constructed world with its own internal logic that begged to be further fleshed out.
This variant requires GURPS Basic at the very least. A full-fledged GURPS Harry Potter campaign requires GURPS Compendium I, Grimoire and Magic as well. GURPS Bestiary, Fantasy Bestiary, Fantasy Folk and Undead are handy, but not essential.