A presentation to the Board of Directors of Boston Library Consortium. Although library collaboration is common and many libraries collaborate through many organizations, it is a relatively unexamined aspect of library work. Many descriptions exist, but little from the point of view of organization and motivation. In this presentation, Constance Malpas and I presented a framework for thinking about library collaboration and draw out some of the challenges successful collaborations face. We emphasized that collaboration is a set of strategic and tactical choices, that it is very influenced by people and politics, and that collective action poses problems.