The present volume is a descriptive grammar of the Jamul variety of Tiipay (also known as Jamul Diegueqo), a Yuman language spoken in San Diego County, California. The nine chapters of the grammar cover the phonology of the language, lexical structure, derivational and inflectional morphology, clause structure, relative and nominalized complement clauses, clause combining (with particular attention to switch reference), and auxiliary constructions. Sample texts and a discussion of discourse are included. In writing the grammar, the author used both textual and elicited data. Elicited data were crucial to the phonemic analysis and formed the basis for the author's understanding of lexical and derivational morphology, ditransitive constructions, reflexives, emphasis on the subject, and certain conjunctions. Discourse data, on the other hand, contributed greatly to the author's understanding of clause structure, switch reference marking, auxiliary verbs, and the use of plural forms.