By organised crime we do not mean simply 'crime that is organised'. Rather, we are interested in organised criminal groups (OCGs) that seeks 'to govern' the underworld. An OCG aspires to obtain a monopoly over the production and distribution of a certain commodity. For us, a mafia group is a special type of organised crime that specialises in one particular commodity, namely protection. More generally, we are interested in how and to what extent illegal and legal markets are governed by criminal groups.