This big folio-size book, with over 50 plates, was all drawn by Hennessy by hand from specimens from personal or university collections. This book is more scientific and botanical in its tone and language choice. It aims to educate a readership already well-versed in the culture of orchids. The first part loses the reader in some technical details and specific nomenclature. The great size of the pages, probably to host the drawings by Hennessy, sometimes represent real-size drawings. They make this book harder to read. It is not a field guide but more a coffee table-type book. Curiously, most African orchids are geophytic or lithophyte orchids with long stems. The flowers can be very small or very big. This book is more of a reference for advanced amateurs and professional botanists than an introductory guide for beginners. It does not include pictures or drawings.