The Onondaga-English/English-Onondaga Dictionary is the result of Hanni Woodbury's thirty years of research and collaboration with contemporary speakers and her study of nineteenth- and twentieth-century text sources. Onondaga is an Iroquoian language spoken at the Six Nations of the Grand River Territory, near Brantford, Ontario, and at Onondaga Nation, near Syracuse, New York. Once spoken by a large Iroquoian population in New York State, Onondaga is now spoken by only a small number of individuals. This comprehensive dictionary is the first of its kind that provides an invaluable tool for the teaching and preservation of the Onondaga language. Many years ago now, the Ontario government and the University of Toronto Press entered into an agreement to publish dictionaries and grammars of the major First Nations languages of Ontario. The orthography employed was developed with the endorsement of Onondaga Nation in New York and the Onondaga speakers at Grand River. The Onondaga dictionary is the fourth Iroquoian dictionary to be published by the Press in recent years. This 2014 edition contains 1536 pages that provides meanings and inflections for each lexical base, as well as cross-references for related bases and additional grammatical, phonological, historical, and cultural information. The appendices, organized under the headings including Nature, People, and Household and Community, feature lists of words that play an important role in daily life. Following an introduction highlighting dialects, the organization of the dictionary, and discussion of the orthography, the Onondaga dictionary begins with a basic grammar of nouns and verbs. This is a clearly written discussion that presents many of the intricacies of Onondaga. It is followed by Onondaga-English and then English-Onondaga entries. This much-needed resource will be invaluable to ongoing efforts to sustain this endangered language. The Press is to be applauded for taking on this commitment. The results have been consistently high quality reference materials that set the standard for work on languages of this family.