This book is essentially a much expanded and updated version of Dressier’s well known ‘The Orchids; natural history and classification’ (1981), without the parts on natural history. Dressier divides the orchid family in five subfamilies: Apostasioideae, Cypripedioideae, Epidendroideae, Spiranthoideae, Orchidoideae. The Epidendroideae have swallowed the Vandoideae, which he recognized in his earlier book. At the tribal and subtribal level there are many changes too. Most of these changes reflect increased knowledge and the results of in-dept studies, and are therefore likely to be improvements. The classification proposed is the most thorough and best-argued one currently available. Much is still tentative, however, and even the number of subfamilies and their circumscription can by no means be considered definitive. Dressler is an open-minded scientist, who never hides his doubts and uncertainties about his own system. He would be the first to point out weak spots in his scheme. In the same spirit I should like to offer some comments and criticisms.