Boris Eikhenbaum spent nearly a decade working within Opoiaz, the Petersburg branch of Russian formalism, to develop a work-centered poetics. Faced with the inadequacy of traditional mimetic, expressive, and pragmatic views of literature, he and his colleagues tried to address literary works without recourse to extraliterary facts. Any intrinsic poetics, however, encounters difficulties, for it must avoid even the most obvious cultural and historical explanations of any work taken as literary. In its struggle against crudely reductive interpretations of literature, Opoiaz had constantly to guard against sliding back into an external approach. This article will suggest that it was largely Eikhenbaum who played the role of guard dog, nudging the evolving Opoiaz view of literature back toward the literary work itself. How successful he was in this effort (and by extension, perhaps, the successes and shortcomings of workcentered literary theories in general) is the question to be examined here. Eikhenbaum's own shift, beginning in 1927, toward a study of literature that privileges the author, may tell us as much about the limitations of objective theories of literature as about the political inadmissibility of Russian formalism under Stalin.