The tax system provides an essential legal framework for the behavior of public and private actors, in particular of private businesses. It ensures the funding of state activities and sets incentives for private entities at the same time. A comprehensive legal analysis of tax rules and principles, therefore, has to encompass both private law and public law as well as both corporate and public finance. Against this background, tax research at the Institute is devoted to tax law within the network of civil law, corporate law and accounting law on the one hand, and the constitutional, European and international background on the other hand. The research is focused – apart from fundamental themes like the rule of law in tax matters – on comparative, European and international business taxation, on legal and policy implications of cross-border tax competition and on the mutual dependence of rule-setting in private law and tax law.