This is the first full-length reference grammar of Mam, a Mayan language spoken today by over 400,000 people in the western highlands of Guatemala and the state of Chiapas, Mexico. The result of over three years of extensive fieldwork in Guatemala, A Grammar of Mam, a Mayan Language is based on the dialect of Mam spoken by 12,000 people in San Ildefonso Ixtahuacan in the department of Huehuetenango, Guatemala. England organizes A Grammar of Mam according to two complementary principles: to analyze Mam following basically traditional levels of grammatical description and to present material in such a way that the background information necessary for understanding each topic of discussion shall have been previously provided. Accordingly, England's analysis of the sound system and morphophonemic processes of Mam is followed by a description of the characteristics of root, inflectional, and derivational morphology. Chapters on phrase structure precede two chapters on sentence-level syntax. A Grammar of Mam is of particular interest in analyzing a Mayan language that is both syntactically and morphologically ergative and that is innovative in the direction of strengthening the ergative system. Indeed at all levels of linguistic organization Mam is innovative, and for this reason it is uniquely interesting both historically and theoretically.