This book provides innovative research on the meaning and dynamics of multilingualism in the specific contexts of "micro-territories". Through the case studies of 10 micro-territories, the book offers a sociolinguistic analysis of two main types of smallness: islands such as Malta, Grenada, Sardinia, the Balearic islands and Taiwan, on the one hand, and small landlocked territories or countries such as Andorra, Aosta, Aran and Luxembourg, as well as the fragmented territory of Catalan-speaking Aragon, on the other hand. Taking into account the notion of micro-territory as a variable, language policies, language use and practices are analysed so as to offer new insights into the way multilingualism is conditioned by demographic and geographical factors. The book contains 5 chapters written in French, 5 in English, and an introduction in French.