This paper traces the history of library cooperation, from early attempts such as the Farmington Plan through successes in tech services and collection development, and from national to international cooperation. The author suggests that the only way libraries can now successfully confront the societal and economic pressures they are now facing is through continued cooperation. This continued cooperation might be realized in the creation of regional repositories, the pooling of information and data, or continued collaboration with creators of information via open access and institutional repositories. Every division of the library, including acquisitions, cataloging, and digitization, will need to be involved in this continued collaboration for the library to continue its success in the twenty-first century.