This book advances the growing area of language policy and planning (LPP) by examining the epistemological and theoretical foundations that engendered and sustain the field, drawing on insights and approaches from anthropology, linguistics, economics, political science, and education to create an accessible and inter-disciplinary overview of LPP as a coherent discipline. Throughout the book, the authors address LPP from different perspectives, exploring the interface between planning in theory and its practical problems in implementation. This volume will be of interest to students and scholars with an interest in LPP in particular, and educational, social, and public policy more broadly.