Recent legislation on Minimum Taxation (Pillar 2 and the GloBE Rules) and the BEFIT proposal from the EU Commission have brought attention to the differences in Effective Tax Rates (ETRs) across individual companies, corporate groups, and countries. Consequently, this growing pressure for fiscal convergence has also rekindled interest among academics and regulators in the relationship between book income and taxable income, commonly referred to as Book-Tax Differences (BTD). Our research contributes to this debate by examining the current European context, analyzing the financial statements of over 420,000 companies and assessing the BTDs and ETRs across 23 countries, revealing significant differences. The factors influencing these differences across countries seem to stem from the interaction between the accounting and financial reporting practices adopted in each State, which, in turn, derive from their respective national fiscal policies. In our view, this study may support scholars and regulators to further explore the potential for corporate tax convergence in Europe through the progressive alignment of ETRs. This "soft approach" could offer substantial benefits: it allows companies to continue preparing their financial statements in accordance with national accounting principles, which are subsequently reconciled through BTDs. Simultaneously; it enables individual countries to maintain autonomy in their fiscal policies, primarily by setting their own nominal Tax Rates (TRs) and implementing various incentives by the regulation of BTDs.