This book is the result of a collective re¬flection among scholars from 8 federations and decentralized countries (Argentina, Australia, Brazil, Canada, Ethiopia, Germany, Italy, Mexico) who sought to update approaches and arguments on federalism in a post-C0VID-19 scenario. On one hand, the pandemic highlighted the importance of federalism to deal with complex intergovernmental problems. On the other hand, federations also faced challenges to coordinate different spheres of government.