The term “monolingual mindset” has its origins in an expression first coined in German by Ingrid Gogolin (1993), “monolingualer Habitus”. It was taken up in its English translation by the late Professor Michael Clyne to describe the perception that monolingualism is the social norm. The monolingual mindset has significant ramifications in the field of language planning and policy and also in its effects on language practices in different domains. The volume under review pays homage to the legacy of Michael Clyne by gathering the work of 18 of his former colleagues and students into a collection of studies that challenge the monolingual mindset in various ways in the areas mentioned.