In 2017, the U.S. adopted the most far reaching changes to its international tax laws since 1962. In the intervening years, the Treasury Department issued significant regulatory guidance. This updated edition reflects these changes. This edition also includes important recent cases. This edition starts with coverage of topics that impact both inbound and outbound taxation. Then, the topic of inbound taxation is addressed. Finally, this edition addresses outbound taxation. This field of study is notoriously complex, more so, perhaps, than any other area of Federal tax law. This edition provides law teachers with a relatively simple, easy to use casebook to teach U.S. international taxation. Consistent with prior editions, this edition focuses on how the details of the tax law fit into a broader structure of both inbound and outbound taxation. The book enables students to fit the particular issues they are working on into a larger policy issues that impact the design of the U.S. international tax laws both in the inbound and outbound context.