Volume 1 of this work was first published in 1985. The present volume refers to 800 species in families Salicaceae to Zygophyllaceae and Cryptogamata. The authors interpretation of 'usefulness' remains as explained in Volume 1 i.e. if a plant is used in any way effectively, it is useful. The geographical area, as shown in the map is unaltered. It has not been practical to keep abreast in the text with political name-changes. The orthography used is the same as in previous volumes and a list is repeated in Volume 5.
