The PALOMERA project set out to understand the policy landscape of OA books and the challenges preventing research funders and institutions in particular from including books in their OA policies. One of the project’s main goals was to support the key stakeholders in the field by providing evidence-based, aligned, and actionable recommendations that can help formulate OA book policies. Open Access books are defined here as scholarly, peer-reviewed books including monographs, book chapters, edited collections, critical editions, and other long-form scholarly works. Textbooks and popular science books are seen as a different category, although the policy recommendations could potentially be extended to this category of books as well when they are published Open Access. Open textbooks are deliberately left out from this definition because they require a different process: policies regarding open textbooks must take into account considerations about Open Educational Resources, which are beyond the remit of the PALOMERA project. In Deliverable 4.2, PALOMERA has developed an extensive set of actionable and aligned recommendations on Open Access (OA) books for eight stakeholders: (1) Research Performing Organisations (RPOs) and research institutes, (2) Public and private Research Funding Organisations (RFOs), (3) National policymakers, (4) Academic and national libraries, (5) Researchers, (6) Learned societies, (7) Infrastructure providers, and (8) Academic publishers. These stakeholders are uniquely positioned to drive a transition to OA books by embedding OA principles for books into their policies and strategies. Since the current landscape of OA book policies is characterised by a lack of policy alignment between various relevant stakeholders, this change requires an aligned effort based on policy recommendations for various stakeholders that are grounded in solid evidence. The evidence for these recommendations has been provided by the Knowledge Base developed in WP2, which contains over 650 open access policy and related documents and a set of 40 stakeholder interviews, as well as on the research undertaken in WP3 which provides a unique overview of the OA books policy landscape in Europe. For each set of recommendations, we have defined a timeline by prioritising recommendations in terms of short term (1-2 years), medium term (3 years), and long term (4-5 years) time frames. The project has performed three validation exercises to check the validity of 1) the data collection and methodology; 2) the analytical approach, methodology, and key findings; and 3) the recommendations themselves. This approach was chosen to increase the engagement with all relevant stakeholders and to strengthen the outcomes of PALOMERA. The recommendations integrate the valuable comments of two reviewers, as well as the constructive comments from the subgroup on scholarly communication of the European University Association’s (EUA) Expert Group on Open Science and the LIBER Working Group on Open Access. Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the Agency. Neither the European Union nor the granting authority can be held responsible for them.