An organelle refers to a specialized subunit of a cell, which performs an important role. Some of the prominent organelles found in plants are mitochondria, nuclei, and plastids. Mitochondria are oblong shaped organelles, which are responsible for providing energy by breaking down carbohydrates and sugar molecules. The nucleus functions as the administrative and information processing center of the cell. Biotechnology has been used for genetically engineering plant organelles for agricultural purposes. Various studies are also being conducted for genome-wide analysis of organellar gene expression and technologies are being developed for selectively manipulating organellar genes and genomes. Such studies are used to study the functioning of organelles. Biotechnology of plant organelles can also be used for improving nutritional quality, crop yield, and resistance to abiotic and biotic stresses. This book contains some path-breaking studies on the molecular biology and biotechnology of plant organelles. Those in search of information to further their knowledge will be greatly assisted by it.