A Reference Grammar of the Onondaga Language is a text-based reference grammar of a highly endangered language. This book is by Hanni Woodbury, Ph.D., an independent scholar who has been researching the Onondaga language since 1971. The Onondaga language is a Northern Iroquoian language spoken by Six Nations of the Grand River territory near Brantford Ontario and at Onondaga Nation near Syracuse, New York. The approach was chosen to insure that the language not be seen through an English filter. The source materials come from many years of the author's own field work, and from extensive documentation of Onondaga texts dating back to the late nineteenth century. Woodbury uses the many text examples to provide detailed and careful explanations of the language's phonological and grammatical processes and takes particular care to explain the technical vocabulary she uses for the convenience of students of the language. Intended as a companion volume to the Onondaga-English/English-Onondaga Dictionary published by University of Toronto Press in 2003, A Reference Grammar of the Onondaga Language is an accessible guide for students and teachers of the Iroquoian languages, and for the non-Iroquoian linguist with interests in comparative work on Indigenous languages and culture.