This book provides a detailed grammatical and lexical description of Makú (Máku), a language isolate formerly spoken in a remote region of northern Brazilian Amazonia. Based on materials collected by researchers since 1912, it documents a language that became extinct around 2000 with the passing of Kuluta (Sinfrônio Magalhães). Makú represents a remnant of a historically diverse and complex ethnolinguistic landscape, largely erased through the expansion of neighboring groups and colonization. The volume includes seventeen annotated texts and is accompanied by approximately 1,000 audio recordings, allowing direct access to 500 examples from the grammatical description, nearly as many vocabulary items, and ten texts, all recorded from Kuluta, providing an invaluable resource for linguists and researchers of Amazonian languages.