This chapter turns to cooperative game theory, which studies how players can form binding coalitions and divide collective gains. It introduces the concept of the core, where no subgroup of players has an incentive to break away, and the Shapley value, which fairly allocates surplus based on contribution. Applications include climate negotiations (e.g., Trump’s Paris pull-out), legislative power-sharing, and online ad markets. Case studies examine Goods and Service Tax (GST) negotiations, coalition politics in Goa, and judicial versus legislative authority.