The document outlines a research program on open access (OA) monograph publishing in the humanities and social sciences (HSS), led by Jisc Collections through the OAPEN-UK initiative. It details various components, including literature reviews, surveys, focus groups, and case studies with key stakeholders such as libraries, publishers, and researchers, aiming to understand the implications and processes necessary for successful OA publication. The gathered data will help inform future policies and practices, while additional resources and events are provided to enhance awareness of OA among HSS researchers.