Debates about decriminalising or even legalising certain narcotic drugs and psychotropic substances have gained much momentum in recent years. On the surface, it appears that more and more jurisdictions are exploring the introduction of measures to permit, albeit in very controlled ways, the use of some narcotic drugs, if only for medical purposes. Others further agree that the so-called ‘war on drugs’ has failed to produce any meaningful success and that new ways to prevent the abuse of narcotic drugs and psychotropic substances need to be explored. Nevertheless, most jurisdictions continue to impose near-complete bans on the production, manufacturing, trade, transport, supply, sale, and possession of illicit drugs. National authorities, along with international organisations, point out that any move to decriminalise narcotic drugs and psychotropic substances is inconsistent with international law. As part of a joint teaching programme on transnational organised crime, students from the Universities of Queensland, Vienna and Zurich researched the topic of illicit drugs in a year-long course. Some of their academic papers are compiled in this volume, addressing topics reaching from international and national legal frameworks to concrete liberalisation efforts in the past and harm minimisation strategies.