This Nutshell, which provides an introduction to U.S. international taxation useful to both U.S. and non-U.S. students and practitioners interested in the topic, has been revised and updated to address the fundamental changes to the U.S. international tax rules introduced by the 2017 tax act, including interpretive regulatory guidance. It also includes discussion of interaction between U.S. tax rules and global tax changes brought about by recent OECD developments as they affect U.S. taxpayers. In addition to providing a survey of the technical rules, the book also offers insight into tax planning considerations and how these have been altered by recent U.S. and global developments. Both the U.S. activities of foreign taxpayers, as well as the foreign activities of U.S. taxpayers are explored. In today’s world, it is crucial for those involved in business and investment activities to understand the tax consequences that impact cross-border flows. The authors’ careers span both the academic and private sectors, and they have used their experiences to distill the complexities of real-world tax considerations into a clearly written, straight-forward presentation of the key international tax concepts.