He did some drugs at university," I said. "Isn't that what it's for? - Ben Aaronovitch

“So the moon effects magic, why?”
“I’m working on several theories,” I said. “But I’m currently favoring the hypothesis that the moon has a seemingly arbitrary effect on magic because it likes to piss me off.”
“That’s a theory with a high degree of applicability to other spheres of life,” he said.

Are you a practitioner?" I ask. "A wizard?"
"Sorceress, my dear," she says. "Practitioner is how the gentlemen have styled themselves, as quacks now style themselves as physicians.

And what they don’t want you to know, you definitely want to know.