A modern approach to understanding the evolution and diversification of land plants, one of the most exciting areas of plant systematics. It consists of three sections - origin and diversification of primitive land plants; origin and diversification of angiosperms; speciation and mechanisms of diversification - each section corresponding to a major area in plant evolution. In each case, data from molecular, morphological, and paleontological approaches are presented, backed by recent progress and new findings, together with proposals for future research. A guide to the latest in plant systematics, heightening awareness of prospective future problems.It is agreed by most scientists that there is a real possibility of mankind's being plunged into crisis around the middle of the twenty-first century because of insufficient crop production to support the explosively increasing world popula? tion and because of serious pollution of the global environment. Plants should play the major role in alleviating this crisis. Consequently, plant science will become of crucial importance in the next century. The application of plant science to crop improvement and the pro? duction of plants resistant to environmental pollution will be achieved through complete understanding of the basic functions of plants. Fun? damental understanding of individual species and the evolution of plants is also important. The Botanical Society of Japan, which was established in 1882, decided to publish a series of special issues of the Botanical Magazine, Tokyo (now the Journal of Plant Research). The aim of this series was to present overviews of recent advances in various fields of plant sciences. As a result, The Botanical Society of Japan published Controlling Factors in Plant Development in 1978, Regulation of Photosynthetic Processes in 1991, and Cellular and Molecular Bio? logy in Plant Cell Cultures in 1993. The contributions to these high-quality special issues were written by leading internalăd