In 1932, Jos Cuatrecasas made his first visit to the high-altitude zones of the northern Andes in South America. He was struck by the rich and complex vegetation of the pramos of Colombia; in particular, the bizarre life-form of Espeletia gave him "the impression of being confronted with a different world." At the time of his death in 1996 at the age of 93, Cuatrecasas had nearly completed his ambitious taxonomic revision of this fascinating group of plants. Seven genera of subtribe Espeletiinae are included here. The 269 botanical illustrations, 60 micrographs, and 190 monochrome photographs provide a wealth of historical, ecological, phytogeographical, anatomical, and cytological information.