An isolated mountain range, 40 kilometres long, in the rain forest of tropical West Africa, Mount Nimba lies at the meeting point of three countries: Liberia, Guinea and the Ivory Coast, the last two both former French territories. In 1942 the French initiated ecological research on their parts of the mountain, discovered its extraordinary interest and the very high number of endemic species, and declared a strict nature reserve. Of the Liberian part nothing was known until the discovery of high-grade iron ore in 1955, and the immediate formation of a company to mine it, led the International Union for Conservation of Nature to start an ecological study there. The authors of this report are respectively the first Director of the research unit which, aided by a grant from the mining company, began work in August 1964, and the chairman of the IUCN Mount Nimba Committee.