Plant cells contain various types of plastid, the best known among which is the chloroplast. Apart from their predominant interest for the work on photo­ synthesis, however, chloroplasts have attracted considerable attention for other reasons. This pertains to extranuclear inheritance of cell organelles and, particularly important for this series, to the participation of chloroplasts as discrete and partly autonomous cell constituents in the developmental biochemistry of plants. This volume is composed of articles by investigators who are actively involved in work on various aspects of research on chloroplasts. Each author has independently covered and analyzed as comprehensively as possible the particular aspects assigned to him. This has the advantage of bringing out many different facets of the situation, though some overlapping has-to be taken into account. We are sure that this volume will enable the reader to gain a broad theoretical and experimental basis for the understanding of the development of chloroplasts and the relationship between plant cells and these organelles.