Although generosity is a wonderful thing, this isn't especially intended as a utopian gesture towards a world in which everything is free. It's recognition of the way in which copies of texts circulate today, a circulation in which the physical object known as the book that is for sale in the marketplace has an important but hardly exclusive role. A PDF of a book is not an illegitimate copy of a legitimate original but participates in other kinds of circulation that have long flourished around the book-commodity: the library book; the photocopy or hand-written copy; the book browsed, borrowed or shared.