Birds have long held a unique dual role as a model group for scientists and as the focus of birders' passionate quests. Despite centuries of observation, each year brings the discovery and description of several entirely new avian species and hundreds of other taxonomic "splits" or "lumps" based on DNA data. In this arena of continual and increasing taxonomic change, The Clements Checklist of Birds of the World is a compendium of the more than 9,800 species of birds recognized by the scientific and birding communities. This completely revised sixth edition incorporates hundreds of updates since the last edition. In taxonomic sequence, it provides the scientific and English name of each species and a description of the worldwide range of each species and subspecies.

The most established resource on the taxonomy and biogeography of birds for the world birding community, The Clements Checklist of Birds of the World is the official world checklist of the American Birding Association (ABA) and is used as the authoritative reference in the birding competitions and listing activities of this preeminent North American organization for serious birders.

- Comprehensive indexes with all taxa listed by English and scientific names
- Tables and maps showing the world distribution of total bird species and endemics by geographic area, which will be of special interest to conservationists
- Space to record the location and date of individual sightings, providing the user with a personalized ornithological journal