This volume treats, through comparative law, the question of the restrictions on private autonomy that increasingly flow from international treaties and national constitutions. While limitations on private autonomy traditionally found their basis in various doctrines in the relevant private law field (such as contracts, property or trusts and estates), it is "higher" law - notably constitutional and international law - that more and more often prescribes those limitations. Until now, this particular interface between "private" and "public" law has seldom been explored, least of all comparatively. This subject was among the topics addressed at the XVIth international congress of comparative law, held in Brisbane, Australia. National reports from 12 countries were presented, as was a synthetic report by the general reporter of the congress for this topic. These general and national reports comprise the body of this new volume.