Historically, comparative study of the skeleton of hummingbirds has focused on systematics, emphasizing differences between hummingbirds and other birds and only rarely addressing differences within Trochilidae. This monograph covers both approaches, and comparisons within Trochilidae are framed within recently published, plausible phylogenetic hypotheses. The data are derived mainly from museum collections of anatomical specimens, covering 256 species of 102 genera of hummingbirds, and 11 genera of other Apodiformes. Although the syringeal skeleton is included, emphasis is on the axial and appendicular skeletons. --