Economic plants have been defined by SEPASAT as those plants that are utilised either directly or indirectly for the benefit of Man. Indirect usage includes the needs of Man's livestock and the maintenance of the environment; the benefits may be domestic, commercial or aesthetic. Economic plants constitute a large and so far uncalculated percentage of the quarter of a million higher plants in the World today. However, it has been calculated that 10% (25 000) of these species are now on the verge of extinction and extinction means that a genetic resource that could be of benefit to Man will be lost for ever. Furthermore, for every species lost an estimated 10-30 other dependent organisms are also doomed. Fewer than 1 per cent of the World's plants have been sufficiently well studied for a true evaluation of the potential floral wealth awaiting discovery, not only in the rain forests, which man is now actively destroying at a rate of 20 ha a minute, but also in the very much neglected dry areas of the World.

Background.- 1. The needs of the people.- 2. The arid environment.- Food.- 3. Wild desert relatives of crops: their direct uses as food.- 4. Crops for arid lands.- 5. The nutritional composition of Australian Aboriginal food plants of the desert regions.- 6. Khoisan Food plants: taxa with potential for future economic exploitation.- 7. Food plants of prehistoric and predynastic Egypt.- Timber, Fuel and Forage.- 8. Place and role of trees and shrubs in dry areas.- 9. Prosopis tamarugo in the Chilean Atacama - ecophysiological and reforestation aspects.- 10. Forage and fuel plants in the arid zone of North Africa, the Near and Middle East.- 11. Forage and browse - the northern Australian experience.- 12. Bees and honey in the exploitation of arid land resources.- Plants for the Environment.- 13. Economic halophytes - a global review.- 14. Present and potential economic usages of palms in arid and semi-arid areas.- 15. Plants for conservation of soil and water in arid ecosystems.- 16. Nitrogen fixation in arid environments.- National Studies.- 17. The potential for the commercial utilization of indigenous plants in Botswana.- 18. Ecodevelopment of arid lands in India with non-agricultural economic plants - a holistic approach.- 19. Sonic indigenous economic plants of the Sultanate of Oman.- 20. The ecological role of plant resources in the arid regions of China.- 21. Plants of the Australian arid zone - an undeveloped potential.- Work of the Royal Botanic Gardens, Kew.- 22. Wild and semi-cultivated legumes as potential sources of resistance to bruchid beetles for crop breeders: a study of Vigna/Phaseolus.- 23. Seed banks: a useful tool in conservative plant evaluation and exploitation.- 24. The potential for the in vitro preparation of a number of economicallyimportant plants for arid areas.- Biochemicals.- 25. Gums and resins, and factors influencing their economic development.- 26. Resins from Grindelia: a model for renewable resources in arid environments.- 27. Plant hydrocarbon resources in arid and semi-arid lands.- 28. Unconventional arid land plants as biomass feedstocks for energy.- 29. Rubber and phytochemical specialities from desert plants in North America.- Information Services.- 30. Plant information service for economic plants of arid lands.- Taxonomic index.- General index.