4) Keep an invention log. Aninvention log is a bound book with paper that cannot be removed or inserted. It is like a diary where you date and document everything you do in regard to creating your invention. You donâ€™t want a binder where you can insert a sheet of paper and manipulate the sequence of events by changing dates. U.S. law does not acknowledge the first to file a patent, but the first to invent. That means that if one person files a patent today for an invention, but over the past year another individual has been conducting research for the same invention, the researcher without the patent pending can show their invention log and prove that they invented the product first.