Contested Languages introduces those languages whose political status is controversial, focusing on the dialetti of Italy that lack official status. The nation state's "one country, one language" ideology is held up as the culprit preventing these languages from receiving the recognition they deserve. Tamburelli and Tosco aren't shy in criticising linguists for failing to advocate for speakers of contested languages. For them, the focus must move away from what people believe to be languages, toward using structural linguistic criteria to define languages and protect minority language speakers.
While I'm sympathetic to this argument, and appreciate their grounded approach to language advocacy, these essays are still largely exploratory and lacking in nuance. Further research is needed on these principles in practice, though this book is a good first start.