The widespread Ceratolejeunea species (liverworts) commonly occur in old secondary vegetation and woody crop plantations and are not threatened. On the other hand, endemic species are very localized in upper elevation areas of the Caribbean and in submontane forests in the northern Andes. These are major centers of species diversity in Ceratolejeunea (Lejeuneacae, the most advanced and the mostly highly specialized family among the leafy Hepaticae). This revision of the genus Ceratolejeunea in Tropical America recognizes 23 species in two subgenera. Included in the volume are keys, descriptions, line drawings, distribution maps, and phylogenetic analyses.