The objective of the conferences was to provide researchers and law enforcement with the opportunity to present their findings to each other in a targeted manner that promotes the health exchange of ideas. The research presented at the conferences has dealt with the complexities of OC and the development of successful counter strategies. The book is divided into four parts, the first three in English and the fourth in German. Part I presents an overview of the research network on organized crime. Part II presents papers from OC Research and Practice in Western Europe: 4th OC Research Conference in Wiesbaden, 2011 that deal with the following: OC crime evolution and its impact in Western Europe; Criminal pathways and involvement in OC; Governing vs. trading: the functional diversification of Mafia activities across territories; Investigating and prosecuting human trafficking in the Netherlands by the National Prosecution Service; XTC production and trafficking in women for the purpose of sexual exploitation; and the impact of drug seizures on local governments. Papers presented in part III were from the OC research and practice conference held in Wiesbaden in 2012 and covered the following: Organized crime in the Nordic countries; the Extent of human organized crime involvement in Finnish human trafficking cases; Local organized crime; Drugs and organized crime in Denmark; and Facing a new criminal setting - A joint agency initiative against organized crime in the municipality of Sodertalje. Part IV of the book contains an overview in German of both the 2011 and 2012 conferences.