Tonight we are talking with Federico Varese about his new book Mafias on the Move: How Organized Crime Conquers New Territories (Princeton University Press, 2011). Whenever you read a book about transnational crime one of the themes will be about how globalisation has made it easier for organized crime groups to operate. You will also see another chapter about how large mafia style groups are spreading outside their traditional domains. But there have been very few studies, other than individual case studies, of how this occurs and what circumstances help or hinder this expansion of operation. Federico takes a rigorous approach to try and answer these questions. He not only looks at how groups expand but also compares successful expansion to unsuccessful cases. He asks what features of the social environment allowed one group to succeed and another to fail. His answers are surprising and they reveal some cumbersome characteristics of large, structured organised crime groups which make it difficult for them to expand their operations to new environments. This is a very enjoyable book to read as it combines detailed stories with strategic data. Federico has clearly put many years of research into this work and the result adds significant new insights for organized crime research.