This is a comprehensive descriptive grammar of Trio, a Cariban language, spoken in the remote rainforest of Suriname and along the border in Brazil. Typologically interesting features of Trio include a basic word order Object-Verb-Subject and a system of evidentiality that expresses whether or not the speaker was eye-witness to an event. Trio has several grammatical morphemes that mirror the group's conceptualization of the world of the visible and the invisible in which they live; one is a facsimile marker that expresses that the denotee of a noun is manifestly but not intrinsically that denotee; the role of the individual in contributing to a" "harmonious collective, recognized by anthropologists as a salient aspect of Amazonian life, is expressed by two -responsibility- clitics. This grammar will be a valuable source-book for linguists, anthropologists, and everyone interested in the finer points of Guianan-Amazonian languages."