CSR and taxpaying are currently a hot topic for academic research. The issue is about securing a sustainable business environment in terms of corporate taxation. A sustainable tax system must be seen from both a collective view and an individual view. The chapter focuses on the individual view. The chapter emphasizes the need for a legal rule-based taxation. The legal order based on the rule of tax law is the only system that in practical terms is able to secure very important functional outcomes. A great problem is that the rule of tax law is the facilitator of tax avoidance and aggressive tax planning. However, CSR and tax morale are important in terms of taxpayer behavior. The most important lesson the social science research provides should be that the willingness to pay taxes is a function of complicated processes and that there is no single explanation as to why an individual or a corporation choose to pay their taxes or to engage or not engage in tax planning or tax avoidance. Research also indicates that the social norm is not very clear in terms of the view on tax avoidance. Ethical norms cannot be described as very clear, either. A very problematic issue is that neither “tax avoidance” nor “fair share” is defined in a way that enables a benchmarking. Evidence implies that a corporate tax strategy is about cost/benefit where “reputational risk” sometimes plays a role. An opportunity is to enhance the use of soft law: the published corporate tax strategies and tax policies. A very brief analysis of a few published tax strategies imply that there is a great potential in that respect. At present, they do not seem to work well as normative instruments. The best way of securing a sustainable corporate taxation is international cooperation on the legislative level and the development of legal concepts against tax avoidance (General Anti Avoidance Rules).