A discussion is provided of the pitfalls that can be encountered when patent applications are drafted abroad and then enter the U.S. patent system. Topics covered are clarity, enablement, best mode, written description, inventorship, publishing the PCT application in English, and citing prior art early. For clarity, grammar and word choice are key, along with a clear exposition of the claim element referred to, since the latter cannot be open to interpretation. For enablement, the invention also must provide enough information to allow a person in the relevant field to understand it sufficiently and to make and use it without excessive experimentation. Best mode is a U.S. law requirement and means that the patent must include what the inventor considers the best way to carry out the invention. The written description is often at issue in U.S. court cases, and, in the U.S., claims have not only to be supported by the specification (as in Europe), but the patent text must also clearly describe to the reader the ways in which the inventor had possession of all claimed matter as of the filing date. As many other countries do, the U.S. requires that inventors be named as the applicants for a patent in order to avoid patent invalidation (which can occur incorrect inventors are listed). Under U.S. law, a U.S. patent can be cited by an examiner as of its filing date, and a PCT application is a U.S. patent application if it is published in English and designates the U.S. In addition, under U.S. law, anyone involved in the preparation and prosecution of a patent application must report any publicly available material if it could lead the examiner to conclude that the claims are either patentable or not patentable.