Background In October 2020, UK Research and Innovation (UKRI) commissioned OAPEN to carry out a gap analysis of technical infrastructure for open access monographs, edited works and book chapters. This report presents the results of the gap analysis. It aims to inform UKRI on infrastructure requirements for OA monographs as part of its considerations for introducing an OA policy for monographs. The report describes high-level workflows and the following stakeholders: author; publisher; (research) institution; funder. The report uses a granular classification of the technical infrastructure supporting OA books and chapters. The scope of the report is to identify infrastructure that either handles open access books exclusively, to a large extent, and/or is key infrastructure for OA books. The focus of this project is on shared technical infrastructure to support OA book publishing for all stakeholders, including all types of publishers and business models. Use cases, workflow and infrastructure The report describes use cases and workflows as a form of information transfer: for sharing both research results and metadata. The following use cases are identified in the report: publish research findings (author); build and manage academic profile; publish research findings (publisher); run repository/library; manage research (institution); manage research (funder); promote open access. The infrastructure is classified into the following areas: publication infrastructure, quality assurance, compliance checking, hosting and delivery, discovery, preservation, monitoring and measuring impact, open access engagement; and advocacy. The infrastructure is used by all stakeholders to perform interconnected tasks. The infrastructure connections consist of metadata about objects such as the manuscript or the research grant. By focusing on the tasks shared by different stakeholders, overlapping interests are revealed. This helps identify gaps in the existing infrastructure. Gap analysis and recommendations The identified gaps occur in most infrastructure areas. There is perceived lack of transparency in monograph publishing, particularly in quality assurance. There should be more attention for best practice in OA book publishing. Authors need to be better supported and have the option to publish their research outputs open access, and funders and institutions need to improve infrastructure to support compliance with policies and monitor research outputs. There are shortcomings in the use of metadata and standards for OA books that limit interoperability and discovery, affecting the wider ecosystem around OA books. The recommendations are to a large extent relevant for the broader stakeholder community and can be considered in the wider context of policy development and measures to improve the infrastructure for OA books.