ts of dealing with independent operators. Networks are connected to content providers that transmit their services over the networks. Platform access is provided when the network owner finds the organi- zational costs of managing the development and supply of complementary services to be greater than the transaction costs of dealing with independent suppliers. In the case of platform access, the relative inefficiencies and reduced creativity of inter- nal provision of complementary services translate into incremental organizational costs. Interconnection of distinct networks can be more efficient than a unified net- work if the additional organizational costs of managing the combined networks are greater than the transaction costs associated with interconnection. The costs of managing a network also include costs associated with providing retail access and procuring services, as well as facilities management. Thus, the cost savings from separate networks that are interconnected also reflect all the operating costs as well as other types of transaction costs. Many diverse telecommunications networks, including wireline telecommunications, mobile telephony, the Internet, and cable telephony, can coexist through interconnection. The market for communications services involves two types of connections. Access refers to market transactions for network services that must accompany connections outside the boundaries of a network. Management transactions refer to connections within the boundaries of the network. The economy's communications systems involve a complex set of interconnections both inside and outside the boundaries of networks. The firms that provide network services by establishing privately owned networks must choose between connections that are external to their networks and connections that are internal to their networks. The economic decisions of firms that provide network services involve choice regarding the boundaries of their networks and interconnections between networks. This suggests that the bou