The Malay city state of Srivijaya, a major actor in world economy between the seventh and the thirteenth centuries, grew at the centre of a complex set of networks encompassing much of the Indian Ocean and the South China Sea. On the basis of a critical review of past studies and the results of recent research in the archaeology and epigraphy of south-east Sumatra and the Thai-Malay Peninsula, this chapter presents a much revised and improved representation of the state and urban formation of this elusive polity, emphasizing the role of trade networks and of accompanying cultural and religious exchange networks, as operated by both local and cosmopolitan actors.