This book explores the ambiguous legal status of traditional–adat–communities in Indonesia and their informal, traditional rights to communal–ulayat–land. It discusses the lack of recognition of adat communities and their legal rights in the Indonesian constitution, surveys legal consideration of informal legal rights both in Indonesia and elsewhere, and examines how thinking about these issues has evolved over time in Indonesia. It provides an in-depth study of the ways that government policies on adat communities are developed, changed and implemented, and how different actors give meaning to these policies, particularly government bodies with authority to manage land and forests, which exercise discretion as to the operational implementation of ideas about adat groups as legal persons and ulayat land rights as land title, thus enabling their exploitation by government and business. The book highlights how these issues are becoming more pressing as problems relating to legal personhood and rights to traditional customary land are increasingly giving rise to violent conflict, dispossession and marginalisation. It also demonstrates how adat communities can take action, and are doing so, to protect their legal positions.