I.1 Why this Book? The mirage of a homogenous globalised world imagined during the latter decades of the 20th century is dissolving. Globalisation, coinciding with a revolution in information technology, at first appeared to point to a gravitational pull towards international languages of wider communication, especially English. Simultaneously, new patterns of migration arising out of a complex mix of sociopolitical and economic tensions, have brought about unprecedented changes which increase linguistic, cultural and faith-based diversity in urban and educational settings. At this time, it has become evident that there are apparent contradictions between the reality of diversity and an aspiration towards homogeneity. These have significant implications for the provision of education if the needs of diverse students for participatory citizenship are to be met. In the South, where diversity has long been acknowledged, there are numerous examples of productive engagement with multilingualism and sustainable development. It is towards some of these examples that this volume turns when the challenges of the UNESCO Decade for Sustainable Development in Education (2005-14) are still before us. The authors in this book illustrate successful advances in, and implementation of, mother tongue-based bi/multilingual education (MLE) despite limited resources in contexts which are spatially dislocated from, or at significant distance from, those which are positioned as at the centre. The purpose of this book is to demonstrate that expertise in the management of sustainable models of education in the so-called ‘peripheries’ offers valuable insights into bilingual and multilingual theory, decentralisation and cost-efficient resourcing of education systems which are sensitive to widely varying student needs.