A trademark is a word, name, symbol, device, or any combination thereof, that is used in commerce to indicate the source of a good or service and to distinguish it from goods or services manufactured or sold by others. Trademark laws exist in the U.S. at both the state and federal levels, and trademarks can be registered with a state government or with the federal U.S. Patent and Trademark Office (USPTO). Federal registration provides greater protection but federal statutes only apply to trademarks used in interstate commerce. The following guide offers a starting point for researching domestic and international trademark law in the University of Iowa Law Library’s collections. Because this guide is selective in nature, researchers should consult with a reference librarian or search InfoHawk, the library’s online catalog, to identify additional materials that specifically address their research needs.