This academic work investigates various approaches for deciding on the grant of preliminary injunctions in patent litigation. These can be a highly effective remedy, but a decision to grant a preliminary injunction is taken early in the course of litigation and often under a cloud of uncertainty. If granted too easily or erroneously, preliminary injunctions can have negative consequences on competition and innovation. The author looks at (judicial) standards that have been developed in various national jurisdictions, Legal theory and Law and Economics. The lessons learned here can be of particular relevance for the future Unified Patent Court.