This dissertation assembled and interpreted archaeological, ethnographic, and archaeometallurgical data in an effort to reconstruct and understand the contributions of iron working technology to the development of Swahili city-states between the tenth and sixteenth centuries AD. Archaeological excavations were carried out at Mtwapa and Galu on the Kenya coast. Additional data from Swahili sites of Ungwana, Mwana, and Shanga was examined for comparative purposes. Ethnographic research was carried out among traditional blacksmiths and ordinary Swahili people in the area. The primary objective of this research was to understand the rQle ofiron technology in the evolution of Swahili villages from fishing and farming societies in the early first millennium AD. into autonomous polities of several towns by the early second millennium A.D. Detailed technical, social, economic, ideological, and political processes of Swahili iron production are reported in this dissertation. Metallographic analysis of a sample of metal artifacts from the Swahili sites was undertaken in collaboration with Professor David Killick. Prehistoric methods of ore and fuel procurement, the methods of forging, and types of artifacts produced were indirectly investigated through ethnographic study of traditional forging techniques still practiced on the Swahili coast. A narrowly-focused single-discipline model of evolution of Swahili societies is rejected in favor of a holistic anthropological one. Bearing in mind the strategic commercial position of the Swahili coast in Indian Ocean maritime trade during the past two millennia, all material cultural elements in the area and especially archaeological artifacts recovered at Swahili sites are treated as products of a culture system whose development may be traced to the east African interior, Arabia, India, China and Indonesia. The Swahili coast had contact with these areas for at least 1500 years before the ani val of the Portuguese in the sixteenth century. Broad inter-site comparisons were needed because the strategic geographical location of the Swahili coast and its inhabitants' possession of sailing technology facilitated interaction with peoples on the African mainland and along the wider Indian Ocean circle. Iron smelting was abandoned on the Swahili coast in the 1850s because of availability of bloom from the interior and industrial scrap from Europe. Forging, however, continued to the present. In response to increased demand for utilitarian items including knives, machetes, hoes, nails, and dishes smithing on the Kenya coast was recently revived thus presenting opportunities to make useful ethnographic studies. Data gleaned from the ethnographic component of the project are critically examined in an effort to complement archaeological and archaeometallurgical data.