This publication has been written in the framework of the European Erasmus+ project “HERMES - Strengthening digital resource sharing during COVID and beyond”, with the aim of promoting a wide reflection about the meaning and practices of resource sharing involving the worldwide information community and fostering the emergence of a common perspective. Resource sharing is an important and long-standing function of libraries, but resource sharing practices are rarely featured in library and information science programs. This publication is intended to provide librarians, library practitioners, as well as teachers, researchers, and students of universities and research organizations and other interested parties, a foundation in resource sharing principles, practices and management. This publication provides an overview of where things stand today with resource sharing, including key trends, challenges, opportunities, and priorities. The publication seeks to address international resource sharing, exploring the current state of European and international resource sharing systems and the governing laws and regulations and includes case studies and best practices from various countries. Despite authors representing ten countries and efforts to seek information from many more, the authors acknowledge that the publication is not exhaustive on all countries, regions, and laws around the world. Instead, this work should be a good point of entry for people new to resource sharing, but also stimulating for experienced professionals. The author’s ambition is for it to become a must-read piece in the wider resource sharing world and inspire more libraries to participate in open resource sharing practices both locally and internationally.