K-D Dijkstra & Asmus Schroter 
Field Guide to the Dragonflies of Britain and Europe: 2nd edition [PDF ebook] 

A revised and thoroughly updated edition of the definitive guide to identifying dragonflies in Europe.
The first edition of the
Field Guide to the Dragonflies of Britain and Europe was a ground-breaking identification guide that led to an increase in Odonata recording across Europe.
The second edition includes fully revised regional guides and identification texts, updated distribution maps and conservation statuses, illustrated accounts for five species that have been discovered in the region since the first edition, updated checklists and taxonomy, and new photographs throughout, as well as an introduction to larvae identification. Each species is lavishly illustrated with artworks of males, females and variations, as well as close-ups of important characters.