This volume surveys (un)successful efforts at language maintenance from around the world in order to ameliorate restorative efforts in a sociolinguistically informed manner. The core chapters deal with: efforts for reversing language shift (RLS); goals of RLS; definition of the endangered status of threatened languages in various sociofunctional domains; evaluation of Irish, Basque and Frisian; language shift in the US involving Navajo, Spanish and Yiddish; the Maori language in New Zealand and the Australian aboriginal languages; the 'success stories' of Modern Hebrew, Québécois French and Catalan; and practical matters of language planning.