Today’s libraries, Apple-era versions of the Dewey/Carnegie institution, continue to materialize, at multiple scales, their underlying bureaucratic and epistemic structures — from the design of their web interfaces to the architecture of their buildings to the networking of their technical infrastructures. This has been true of knowledge institutions throughout history, and it will be true of our future institutions, too. I propose that thinking about the library as a network of integrated, mutually reinforcing, evolving infrastructures — in particular, architectural, technological, social, epistemological and ethical infrastructures — can help us better identify what roles we want our libraries to serve, and what we can reasonably expect of them. What ideas, values and social responsibilities can we scaffold within the library’s material systems — its walls and wires, shelves and servers?