Book excerpt: Endangered Languages in the 21st Century provides research on endangered languages in the contemporary world, the challenges still to be faced, the work still to be done, and the methods and practices that have come to characterize efforts to revive and maintain disadvantaged indigenous languages around the world. With contributions from scholars across the field, the book brings fresh data and insights to this imperative, but still relatively young, field of linguistics. While the studies acknowledge the threat of losing languages in an unprecedented way, they focus on cases that show resilience and explore paths to sustainable progress. The articles are also intended as a celebration of the 25 years’ work of the Foundation for Endangered Languages, and as a parting gift to FEL’s founder and quarter-century chair, Nick Ostler. This book will be informative for researchers, instructors, and specialists in the field of endangered languages. The book can also be useful for university graduate or undergraduate students, and language activists. The Open Access version of this book, available at www.taylorfrancis.com, has been made available under a Creative Commons Attribution-Non Commercial-No Derivatives 4.0 license.