Mosetén belongs to the small, unclassified language family Mosetenan and is spoken by roughly 800 people in the foothills of the Bolivian Andes and the adjoining lowland region. This book provides a grammatical description of Mosetén in the form of a descriptive reference grammar. It is based on the author's extensive fieldwork in Bolivia and is intended to be comprehensive and aimed at linguists from all backgrounds. Belonging to an unclassified language family, Mosetén is of special interest to typologists, historical linguists, contact linguists and South Americanists. The grammar is divided into a chapter on phonology (2.) and six chapters on the morphology: morphological processes (3.) the nominal system (4.), pronouns and reference (5.), adjectives and adverbs (6.), quantification (7.) and the verbal system (8.). These chapters are followed by voice (9.), negation (10.) and modality and discourse markers (11.). Finally, there are two syntactically oriented chapters on clause types (12.) and clause combinations (13.). In the appendix, three types of texts, a list of morphemes, a list of references and further bibliographical notes are added. Furthermore, there is an index. This grammar is the first accessible and comprehensive description of a Mosetenan language.