This is a folding pocket guide devoted to the callitrichids, among the most widespread and engaging of New World monkeys. This folding guide presents colour illustrations and detailed range maps for all seven genera now recognized within the Callitrichidae: the pygmy marmoset (Cebuella), the dwarf marmoset (Callibella), the Atlantic and Amazonian marmosets (Callithrix and Mico), the tamarins (Saguinus), the lion tamarins (Leontopithecus) and the enigmatic Goeldi"s monkey (Callimico). Each of the sixty-one callitrichid taxa is illustrated by the primate artist Stephen Nash, and accompanied by notes on geographic distribution as well as current threat status on the IUCN Red List. The folding guide also includes overview maps showing the distribution of species groups throughout the Neotropics, plus a checklist of all taxa for primate-watchers to record their sightings. Laminated for durability and weighing less than a newborn tamarin, this newest folding guide will be a valuable resource for travelers from Panama to Parana.