The world is becoming increasingly global. This raises important challenges for regulatory processes which still largely emanate from domestic jurisdictions. In order to eliminate unnecessary regulatory divergences and to address the global challenges pertaining to systemic risks, the environment, and human health and safety, governments increasingly seek to better articulate regulations across borders and to ensure greater enforcement of rules. But, surprisingly, the gains that can be achieved through greater co-ordination of rules and their application across jurisdictions remain largely under-analysed. This volume complements the stocktaking report on International Regulatory Co-operation: Rules for a Global World by providing evidence on regulatory co-operation in four sectors: chemical safety, consumer product safety, model tax convention, and competition law enforcement. The four case studies follow the same outline to allow for comparison.