Chloroplast development is a key feature of leaf developmental program. Recent advances in plant biology reveal that chloroplasts also determine the development, the structure and the physiology of the entire plant. The books, published thus far, have emphasized the biogenesis of the organelle, but not the events associated with the transformation of the mature chloroplast to the gerontoplast during senescence. This book, with 28 chapters, is unique because it describes how the chloroplast matures and how it is subsequently transformed to become the gerontoplast during senescence, a process required for nutrient recycling in plants. This book includes a state-of-the-art survey of the current knowledge on the regulation and the mechanisms of chloroplast development. Some of the chapters critically discuss the signaling process, the expression potential of plastid DNA, the interaction of cellular organelles, and the molecular mechanisms associated with the assembly and the disassembly of organellar complexes and finally the modulation of chloroplast development by environmental signals.