On June 1, 2023, the new European Unified Patent Court (UPC) opened its doors, and enforcement of European patents in (currently) 17 contract member states is now possible with one action. This series of articles – directed at U.S. practitioners trying to familiarize themselves with the basic features of the UPC – aims to provide a high level view of the key aspects of the UPC system, compare them to patent litigation in the U.S., and consider their implications on U.S.-European parallel patent litigation.