"Review of Research in Education: Vol. 38, Language Policy, Politics, and Diversity in Education" explores the role of educational language policies in promoting education as a human right. There are an estimated nearly 7,000 living languages in the world. Yet, despite the extent of language diversity, only a small number of the world's languages are used as mediums of instruction. Even in English-dominant countries, such as the United States, it is important to understand the role of educational language policies (ELPs) in promoting educational access through the dominant language, and its impact on educational equity, achievement, and students' sense of identity. A central question of importance taken up by the authors in this volume is whether language minorities should have a right not only to linguistic accommodation but also to the promotion of their languages as a means for developing a positive identification with their languages and cultures. Other questions about the impact of educational policies relate to the differential statuses of language minorities and the failure to recognize speakers of minority languages. Many countries attempt to neutralize linguistic diversity by promoting a "common" or "national" language. This strategy can have negative consequences for both minorities and speakers of the dominant language if the majority population disassociates itself from language minorities or uses minority languages to stigmatize minority populations. The role of English as the world's dominant language or lingua franca also poses challenges (see Shohamy, Chapter 11). In many countries around the world, English is a required subject in school and increasingly for university admission (Jenkins, 2013). It is also increasing as a medium of instruction, especially in mathematics and science instruction. Thus, the impact of English language educational policies as well as that of other dominant languages in a global context are subjects worthy of consideration (see Tollefson, 2013; Tollefson & Tsui, Chapter 8). Another focus of this volume addresses the importance of other major languages within the context of global economic, political, and cultural contexts. Given the large number of speakers of Spanish in both global and U.S. contexts, it is also important to consider the implications for ELPs (see the chapters by García, Chapter 3, and Macías, Chapter 2). Despite the presence of over 35 million Spanish speakers in the United States, Spanish continues to be taught primarily as a "foreign" language. As Macías (Chapter 2) notes in his chapter, the historical role of Spanish in the United States is complex but the case may be made for its status as a conational language of the United States. Finally, within most countries and increasingly within the United States, there are many languages that play an important role as heritage and thriving languages of immigrant and indigenous communities. Thus, this volume also addresses the importance of considering policies related to these languages and their speakers. Similar to the changes we are experiencing in the natural world, language diversity is in flux due to large-scale trends with widespread implications that affect every nation. This timely volume arrives at a crossroads in the course of these global shifts. The authors' perspectives provide a solid intellectual grounding from which to inform the consequential policies and programs that will shape the educational and social environments for millions of students worldwide.