This historic volume, part of the "Transdisciplinarity Today" collection, is a compilation of contributions presented at the online symposium "For an International Transdisciplinary Chair," organized by the International Center for Transdisciplinary Research and Studies (CIRET) from March 21-25, 2024, in Paris.  The event started the celebration of thirty years since the signing of the "Charter of Transdisciplinarity," an essential document that has defined the direction of transdisciplinary collaboration and understanding.