In unifying private law, the international community initially made use of treaties since the subjects of the early years before World War I were conceived of as affecting national sovereignty. As this tool proved functional, it was subsequently retained as the vehicle of »pure private law« unification. In more recent times an increasingly varied number of legal forms can be observed. However, whereas model laws and principles facilitate a spontaneous approximation of laws and allow for the interpretation and supplementation of conventions in legislation and practice, they do not unify the law. Both tools thus have their limits. The institutionalization of legal unification started after World War II; it has meanwhile acquired a very comprehensive character. There is hardly any subject not capable of being treated by a specialized international agency. In many areas international organizations have also taken the political lead in the unification of laws. The task of safeguarding the consistency of private law in this multi-voiced concert is incumbent on UNIDROIT, UNCITRAL and the Hague Conference. In recent decades, a new actor has entered the scene: the European Union. As regards the unification of laws within Europe, it has ousted other international organizations. By necessity the other organizations have relocated the centre of their activities to the extra-European, universal field. The EU has become active in that context as well: as a party to universal conventions, not as a producer of uniform law. The interpretation of uniform law has to a large extent come to be understood as autonomous interpretation taking into account the insights provided by comparative law. With regard to gap-filling, recourse should be had to general principles governing the respective area of law at issue. In the long run, the aim of uniform law application cannot be achieved without institutional arrangements such as the referral of preliminary questions to an international tribunal. The traditional approach of amending protocols has proven unsatisfactory for adapting aging conventions to a new environment because of the inherent uncertainty and time-consuming nature of ratification procedures. New approaches in some conventions demonstrate that simplified revision procedures are possible and promising.