Print book collections are facing significant transformation in response to mass digitization, remote storage, and preservation. These issues should be considered within a system-wide context in which individual print book collections are viewed not as isolated units, but rather as parts of a larger whole. As libraries look beyond the boundaries of their local print book collections to consider system-wide implications, they will need to be equipped with data and analysis about the system-wide print book collection. This paper provides a brief overview of the system-wide print book collection, defined as the combined print book holdings of libraries everywhere, as reflected in the WorldCat bibliographic database. Issues addressed include the size of the collection; holdings patterns; distribution by publication date and language; and the relationship of the system-wide print book collection to overall book production. The paper concludes with a brief discussion of some implications of the analysis, and possible directions for future research.