This paper is a critical reconstruction of Luciano Floridi's view of librarianship as "stewardship of a semantic environment," a view that is at odds with the dominant tradition in which library and information science (LIS) is understood as social epistemology. Floridi's work helps to explain the normative dimensions of librarianship in ways that epistemology does not, and his Philosophy of Information frames librarians' traditional stewardship role in terms appropriate for our growing involvement in the management and preservation of information through its entire life cycle. Floridi's work also helps illuminate what is coming to be called "knowledge as a commons." Librarianship is concerned with maintaining and enhancing information environments over time, environments that include the behavior of the people who create and use them. The integrity of these environments makes possible the epistemic projects of faculty, students, and other researchers, but librarianship is not, itself, epistemological. Floridi's ecological reframing of philosophy of information and information ethics, bridging the dichotomy between information and user, has a variety of implications for information literacy education and other academic library services in higher education.