Although the only publication with a realistic claim to the title "The plant diver sity of Malesia" is Flora Malesiana itself, we have hesitatingly chosen this title for the present proceedings volume. Past, present and future work on the Flora Malesiana project was the subject of a successful symposium held in August 1989. This book contains only a selection of the papers presented at that meet ing, yet it covers a much greater diversity of themes than just the inventory of botanical diversity. It even goes beyond the boundaries of the vast Flora Malesi ana region in several of its chapters. The role of the founder of the Flora Malesiana Project, Professor C.G.G.J. van Steenis, repeatedly recurs in several chapters; not only as director of and contributor to the project, but also as a pioneer in the fields of Malesian vege tation, conservation and biogeography, and as an enlightened systematist whose ideas and practical recommendations for taxonomic delimitation still largely apply. Botanical information made available in regional and local floras is of vital im portance for applications such as the exploitation of natural forests on a sus tainable yield basis. for establishing gene banks for the benefit of agriculture. forestry and horticulture. and not in the least for nature conservation. Several chapters are devoted to these themes. Floristic studies are also at the basis of the biogeographical essays and vegetation studies included in this book.