Handbook of the Birds of the World: Complete Series

Material in each volume is grouped by families, with an introductory text on general aspects of the group, generously illustrated with colour photographs. This is followed by individual species accounts and their accompanying colour plates illustrating all species, including all significant sexual and subspecific differences, of all of the families covered. In addition, all volumes contain a foreword on a particular ornithological theme. Volumes average 600 pages of full-colour content and deal with 500 to 800 species, with 60-plus plates, hundreds of photographs and distribution maps, and thousands of references. So far, 11 volumes have been produced. New volumes appear at roughly annual intervals, and are collected by scientific organizations, birdwatchers and wildlife enthusiasts in over 150 countries.