In one of the most thorough studies ever prepared of a California language, Hill’s grammar reviews the phonology, morphology, syntax and discourse features of Cupeño, a Uto—Aztecan (takic) language of California. Cupeño exhibits many unusual typological features, including split ergativity, that require linguists to revise our understanding of the development of the Uto—Aztecan family of languages in historical and areal perspective.