Established in 1960, Cuc Phuong is the oldest national park in Vietnam located in low mountains about 100 km SSW of Hanoi. The mountains in this area are remnants of a highly eroded ancient limestone plateau composed of crystalline limestone which originated from marine deposits accumulated more than 200 million years ago. The spectacular rocky landscape of the national park provides specific habitats for a unique and very rich flora including numerous local endemics. This is a globally important example of a lowland rocky limestone plant formation and the only remaining large area of lowland limestone forests within north-eastern Indochina. This book presents results of the up-to-date inventory of the orchids in the national park based on studies of all available collections and field explorations of the authors since 1985. It includes 110 species in 56 genera. Some of these orchids represent strict local endemism and survive today only within the national park. Standard taxonomic treatments presented in the book include keys for orchids identification, correct names, main synonyms, short morphological descriptions, data on their flowering season, distribution, and notes on taxonomy, biology and their possible use. The glossary of orchid terminology presented in the book includes list of 362 scientific botanical terms as well as 12 plates of line drawings which illustrate many of the terms. The book is illustrated with 1 map, 1 diagram, 184 color photographs, 29 line drawings.