Petrus C. van Duyne Aristotelian dimensions in organised crime research; Miroslav Scheinost Twenty-eight years of expert surveys on perceived trends in organised crime in the Czech Republic; Paul Larsson Policing organised crime; Anita Lavorgna You can’t judge a book by its cover. Expounding gangmastering as organisational crime; Stefano Becucci Nigerian criminal cults in Italy. Internal organisation and main illegal activities; Petrus C. van Duyne and Jackie H. Harvey Grand corruption in Nigeria: Nigeria’s grabbing political elite; Klaus von Lampe ‘Clan crime’ in Germany. An examination from the perspective of the study of organised crime; Brendan Quirke Conflict Minerals. The hidden cost of technology; Petrus C. van Duyne, Anna Markovska and Alexey Serdyuk The organisation of eco-crime and corruption in ‘green’ Ukraine; ii Toine Spapens Manure fraud in the Netherlands:a rural green perspective 269 Adriano Francescallengi The role of Customs Laboratories in fighting hydrocarbon crime in Europe; Gabriëlle op ’t Hoog and Linette de Swart The role of asset recovery teams in the fight against subversive crimeIn peer reviewed contributions international experts present a broad range of criminal phenomena and policies.This volume contains the contributions of the 21st Cross-Border Crime Colloquium webinar hosted by the Norwegian Police University College, Kongsvinger and organised 22-24 August 2021. Despite the pandemic, the Colloquium Group decided to return to the ‘criminal normal’ and the related research on (cross-border) organised crime, corruption, labour exploitation, fraud, ecological crime and the search for criminal revenues. These are partly old themes, some getting renewed attention, such as the hidden wealth of corrupt political elite, whether Nigerian godfathers or Russian oligarchs.A criminal theme with global implications is the growing ‘greencriminality’ or crime against the nature. Forests are illegally cut clear in Eastern Europe to satisfy the hunger of the European furniture industry: cheap furniture from stolen wood from the Carpathian or further east leaving behind devastated landscapes. Also, criminal waste traffi ckingfrom industrialised farming fi nding its way through criminal channels is a recognised cross-border organised crime.In peer reviewed contributions international experts present a broad range of criminal phenomena and policies: from a 25-year review of organised crime in The Czech Republic, labour exploitation and Nigerian organised crime in Italy, Middle-Eastern criminal clans in Germany, and international fuel fraud to criminal asset recovery policy in the Netherlands.