This book presents the first grammatical description of Andakí, an extinct language and presumed isolate once spoken in southern Colombia. Written in an accessible style, this book is valuable to both linguists and scholars of South American indigenous cultures. Although Andakí was documented to some extent in the late 18th and early 19th centuries, its grammar has never been systematically analyzed until now. Drawing on sometimes fragmentary data, all made available in an online database, the book offers the most complete grammatical description of Andakí to date and highlights connections to neighboring languages where relevant. This study provides essential groundwork for future comparative research and contributes to preserving the linguistic heritage of one of the world’s most linguistically diverse regions.