Publishers, libraries, and a diverse array of scholarly communications platforms and services generate information about how OA books are accessed online. Since its launch in 2015, the OA eBook Usage Data Trust (@OAEBU_project) effort has brought together these thought leaders to document the barriers facing OA eBook usage analytics. To start addressing these challenges and to understand the role of a usage data trust, the effort has spent the last year studying and documenting the usage data ecosystem. Interview-based research led to the documentation of the OA book data supply chain, which maps related metadata and usage data standards and workflows. Dozens worldwide have engaged in human-centered design workshops and communities of practice that went virtual during 2020. Together these communities revealed how OA book publishers, platforms, and libraries are looking beyond their need to provide usage and impact reports. Workshop findings are now documented within use-cases that list the queries and activities where usage data analytics can help scholars and organizations to be more effective and strategic. Public comment is invited for the OA eBook Usage Data Analytics and Reporting Use Cases Report through July 10, 2021.