In 1983, the American Birding Association (ABA) accepted Clement's Birds of the World as the standard for species found outside of the ABA and AOU Checklist areas. Besides the world listers, I imagine many traveling birders will find this reference volume useful as an organized list of recognized subspecies and for clarification of common bird names. Those who own the complete set of Handbook of the Birds of the World (Lynx Edicions) can find similar information, but not in such a convenient format. There are of course other checklist out there. Edward Dickinson's 3rd edition of the Howard & Moore Checklist (2003) has been well-recieved, not least because of the much more extensive cross-referencing to the scientific literature and the bibliography contains ~3,000 items. A 4th edition is expected in 2009.
Turning back to Clements, I keep gazing at the exquiste cover photograph of a male Banded Pitta by Wicha Narungsri, which evokes fond memories of Thailand's broadleaf forest.
Title: The Clements Checklist of Birds of the World
Author: James F. Clements.
Publisher: Cornell University Press.
Pages: 844 pages, 8 3/4 x 11 1/4, tables, maps.
Published: June 2007.
Retail Price: U$59.95.