United States tax matters can be confusing to even the most seasoned American expat. In addition, although they may not realize it, foreign persons with US connections may also be impacted by US tax issues. Many non-US persons have a connection to the USA in some manner. Perhaps a family member is married to a US person; perhaps a family member has been studying in the US and may decide to remain there or to get a green card. Other connections can exist such as the desire to purchase US real property as an investment or a vacation home; or a desire to invest in the US securities market; maybe the family has a business which is now taking on US connections, for example, by selling goods or providing services into the US. In any such instance, US tax issues must be considered and planned for.
My free US Tax Primer for Expats and Foreigners is a great guide. Get all the information you need right at your fingertips.