This thesis looks at what it means to be modern in a village of Siang Dayak people in Murung Raya Regency, Central Kalimantan, Indonesia. It asks: What new forms of social organisation have emerged in the context of modernity, and what is their impact? In the wake of decentralisation, the New Order era ‘development state’ has been recreated at the regional level, and Indonesia’s regencies have become significant loci of governance and business activity. Development rhetoric is often invoked to justify the activities of large-scale private enterprises operating in Indonesia’s regencies. Nine years old at the time of research, mineral-rich Murung Raya Regency provides a revealing case study of the effects of decentralised development on ‘peripheral’ Indonesia, its landscape and its people. The Siang language group, indigenous to Murung Raya, is poorly documented. Based on indepth ethnographic research, this thesis presents the most comprehensive study of the Siang community to date and has two main objectives: to fill a gap in the ethnographic literature by documenting life in a Siang village and, in doing so, to look at the effects of the expansion of modern discourses and institutions on one group of Indonesians who are often problematised as being ‘underdeveloped’. In documenting life in a Siang village at a time of rapid modernisation, this thesis is an exploration of both the nature of Siang society and modernity itself. The Siang have become increasingly subaltern as Murung Raya is ‘developed’ and, in this context, I characterise them as a subaltern group. Development is bound up in wider power structures that I explain using the theories of Foucault, Gramsci and Weber. Development discourse, which I argue is hegemonic, functions as a Foucaultian power/knowledge structure. However such discourse analysis alone does not account for the economic and political entanglements of development, or the underlying threat of violence, which can be better explained in Gramscian and Weberian terms. I also employ post-development theory in order to explain the form and function of ‘development’ in Murung Raya, although postdevelopment theory does not account for the nuances of field-specific contexts, which I address with original field data. I argue that although the Siang and other indigenous ‘Dayak’ peoples have long been a part of international trade networks, their relationship with foreign markets has fundamentally changed in the era of global neoliberalism, resulting in dispossession and disempowerment, and rendering the Siang to the position of subalterns. The thesis details the effects of this changing relationship on Siang social organisation, ritual practice and livelihoods.