Keeping world-leading international law resourceopen access

30 March 2026
1 min read

ճ   has reached its goal for renewals and will continue to publish on a Subscribe to Open model, through to at least March 2027.

ճMax Planck Encyclopedia of Public International Lawisthe leading resource in the field,containingpeer-reviewed articles on every aspect of international law—adisciplinewhichprovides a common legal framework for the whole world.

By convertingthiscomprehensive, analytical resourcetoan open access,Subscribe to Open model,wehave made it possible for students, scholars, practitioners, and governmentsworldwideto access this content freely without financial barriers. 

Subscribe to Open in practice

ճMax Planck Encyclopedia of Public InternationalLawisOUP’sfirst experiment with the Subscribe to Open model – a modeltypically applied to journals rather than books. Thanks to the support of ourinstitutional and librarycustomers, this valuable content is freely accessibleto allfor a second year.

As a result of theSubscribe toOpen model, usage of the encyclopaedia has increasedsubstantiallyfrom2024 to 2025:

  • An increase in usage by 1,291%
  • An increase in usage from low- and middle-income countries by556%
  • Access from users in235  different territories around the world, anincreasefrom 199,includingall196 United Nations member states.

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

“We are delighted to have this opportunity toparticipatein a pioneeringopenaccessproject, particularly in view of the foundational role played by the Max Planck Society in launching the move towards open scholarship.Openaccesscan contribute to epistemic justice and pluralism—and what we call “encyclopaedic knowledge” should not only be distributedfreely, butalso 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.”

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

Find more information, including about renewals, .

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