Keeping world-leading international law resource open access

The Max Planck Encyclopedia of Public International Law  has reached its goal for renewals and will continue to publish on a Subscribe to Open model, through to at least March 2027.  

The Max Planck Encyclopedia of Public International Law is the leading resource in the field, containing peer-reviewed articles on every aspect of international law—a discipline which provides a common legal framework for the whole world.  

By converting this comprehensive, analytical resource to an open access, Subscribe to Open model, we have made it possible for students, scholars, practitioners, and governments worldwide to access this content freely without financial barriers. 

Subscribe to Open in practice  

The Max Planck Encyclopedia of Public International Law is OUP’s first experiment with the Subscribe to Open model – a model typically applied to journals rather than books. Thanks to the support of our institutional and library customers, this valuable content is freely accessible to all for a second year.  

As a result of the Subscribe to Open model, usage of the encyclopaedia has increased substantially from 2024 to 2025:

• An increase in usage by 1,291%  

• An increase in usage from low- and middle-income countries by 556% 

• Access from users in 235  different territories around the world, an increase from 199, including all 196 United Nations member states. 

Professor Anne Peters, Director at the Max Planck Institute for Comparative Public Law and International Law, Heidelberg, and General Editor of the Max Planck Encyclopedia of Public International Law, said:  

“We are delighted to have this opportunity to participate in a pioneering open access project, particularly in view of the foundational role played by the Max Planck Society in launching the move towards open scholarship. Open access can contribute to epistemic justice and pluralism—and what we call “encyclopaedic knowledge” should not only be distributed freely, but also be built up from a globally diverse set of standpoints.” 

Rhodri Jackson, Director of Open Access Publishing and Strategy, shared:

“Innovation in open access models is in line with our mission: not only to publish excellent research and scholarship but to make it available worldwide. We are committed to learning from all our initiatives—successful and less successful—and to sharing our results transparently. The first year of Subscribe to Open for the Max Planck Encyclopedia of Public International Law has been a great success and we’re excited to see what happens in year two.”

While we have reached our goal for renewals this year, we still need to reach our renewal goals annually to keep this resource open access. By renewing your subscription, you help to ensure that this valuable resource remains open and accessible to all, year after year.” 

Find more information, including about renewals, here.