This book explores the taxation systems of the top 10 economies by nominal GDP in 2025, comparing their structures, assessing their progressivity or regressivity, and evaluating the facilities they provide to citizens. What similarities emerge in how these economic giants raise revenue? How do their tax policies influence inequality? And how effectively do they convert taxes into tangible benefits like healthcare, education, or infrastructure? By analysing these questions, we uncover the trade-offs between revenue generation, economic competitiveness, and social equity.