SUMMARY. Our prevailing models for library collections and collections cooperation emerged in the analog era. The electronic environment has changed the terms of both analysis and activity. This paper explores four aspects of the shift. The relationship between de facto systems and explicit cooperative frameworks, and the conceptual framework for library collections, reflect the mental models with which we structure our activities. Both require a new look. The Janus Conference, held at Cornell University in the fall of 2005, sought to recast the agenda for research library collections and cooperation in the digital age. The meeting's prospects and implications, as of the spring of 2006, are thus surveyed as well. Actual responses to these challenges, finally, are likely to play out differently across specific segments of our library community. This dynamic provides a final focus for comment, doi: 10.1300/J111 v46n02_08 [Article copies available for a fee from The Haworth Document Delivery Service: 1-800-HAWORTH. E-mail address: <docdelivery@haworthpress.com> Website: <https://www.HaworthPress.com>; © 2007 by The Haworth Press, Inc. All rights reserved.]