This report documents the design, methods, results, and recommendations of the Next Generation Library Publishing (NGLP) project team’s 2019-2021 study of library publishing infrastructure gaps and requirements. This research was designed to accomplish two related goals: to reveal and chronicle library publishing stakeholders’ current needs, interests, and desires regarding the tools and environments that support their publishing activities to develop a meta-understanding of the open-source tools and environments available for publishing, how those tools and environments might be combined and built upon, and where gaps between them might be mitigated through standards, scripts, and documentation. Based on our research interactions with more than 150 library publishing stakeholders, we have identified the remarkably consistent needs and desires of library publishers today, including the following: Ways to integrate existing platforms and tools rather than building new ones Unified web delivery and discovery options that work across those platforms An administrative dashboard that can provide central control and reporting options Choices among a range of hosted, turnkey solutions Community-led, rather than commercial, modes of governance and sustainability for tools, platforms, and service providers This report seeks to make all of our research findings available to and usable by other teams—including projects, tool developers, service providers, and communities of practice. We hope many can use this synthesis of our research to inform their understanding of the interests, needs, gaps, and opportunities in the growing library publishing field. We are grateful for the generous support of this work by Arcadia – a charitable fund of Lisbet Rausing and Peter Baldwin. We also deeply appreciate all of the diverse stakeholders in library publishing who engaged in our interviews, focus groups, workshops, and other sessions in 2019-2020.