from the Frequently Asked Questions: This book is not what it might seem. First and foremost, this is a book of choices. Great pains have been taken to not create new rules, restrictions, or requirements. Adding this book to your current OSR game should not make it more complex or cause your Referee to develop many more headaches or involuntary tics than usual. Everything in this book can be ignored without peril. announcement on The Piazza: The Basic Illusionist, contains the illusionist class and one subclass (the mountebank), plus 24+ pages of spells (154 spells, actually), suggestions for running illusions, playing illusionists, and 3 illusion-related monsters.