The initiative that emerged from these discussions within ARL came to be known as the “Cloud Library” project, because it posited a future in which library collections and services would be sourced from external providers, reducing local infrastructure and operational expenditures in a manner analogous to the cloud-sourced business and computing solutions that now prevail in the commercial and high-tech sectors. Funded by The Andrew W. Mellon Foundation, the project was staffed by a team of investigators from the HathiTrust, the Research Collections Access and Preservation consortium (ReCAP), New York University Libraries, and OCLC Research. This report provides a.