This book provides a comprehensive guide to the modern U.S. international tax system, focusing on the structural reforms introduced by the Tax Cuts and Jobs Act (TCJA) and their interaction with global tax initiatives. It explains key regimes such as Subpart F, GILTI, FDII, and BEAT, along with the foundational concepts of foreign tax credits, controlled foreign corporations, and international tax modeling. Through analytical frameworks, calculation methodologies, and practical case studies, the book helps readers understand cross-border tax planning, compliance requirements, and financial reporting implications. It is designed for tax professionals, corporate finance specialists, researchers, and policymakers involved in global taxation and multinational enterprise operations.