This book provides a comprehensive guide to the U.S. international tax system and financial modeling techniques used in multinational tax planning and compliance. It explains the structure of cross-border taxation, including foreign tax credit rules, controlled foreign corporations, functional currency calculations, and previously taxed earnings and profits (PTEP). The text integrates financial modeling frameworks with international tax regulations, enabling readers to analyze complex multinational corporate structures, cross-border transactions, and tax optimization strategies. It also examines transfer pricing documentation, international tax reporting forms, and cross-border reorganizations, while highlighting the growing role of data automation tools and digital compliance systems in modern tax administration. Designed for tax professionals, financial analysts, and researchers, the book offers practical insights into global tax compliance, modeling, and strategic decision-making in multinational enterprises.