The Yungas are highly biodiverse cloud forests extending from Venezuela south through NW Argentina, and are considered one of the biodiversity 'hot spots' in South America. This bilingual (Spanish/English) pocket field guide, the first of its kind for any region in South America, is accompanied by 280 illustrations including detailed diagnostic drawings and numerous color photos of live dragonflies. It covers all 102 species in 45 genera and 9 families found in the Argentine Yungas, representing over a third of all species known from the country. This guide provides a reliable and original means of identifying adult odonates for limnologists, ecologists, biologists, naturalists, amateurs and to anyone interested in the aquatic ecosystems of the cloud forests of the South American Andes, their biota and conservation. Natalia von Ellenrieder is a researcher for the CONICET (Consejo de Investigaciones Cientificas y Tecnicas) at the Instituto de Bio y Geociencias in Salta, Argentina, and Rosser W. Garrison is an Insect biosystematist at the California Department of Food and Agriculture in the US.