Target audience: Anyone interested in Breton; students of Celtic studies. Breton (Ar Brezhoneg) is a language of Celtic origin, primarily spoken in western Brittany. With around 30,000 Breton and 40,000 German keywords and phrases, this is the most comprehensive and modern dictionary of its kind to date, covering everyday and literary language as well as specialized vocabulary. The inclusion of idioms and proverbs also provides insights into Breton ways of thinking. The clear structure of the keyword articles, the indication of pronunciation for the keywords, grammatical information, and notes on correct usage make this dictionary a reliable tool. Conjugation and declension tables complement the Breton-German vocabulary list.