Chloroplast refers to a type of membrane-bound organelle that conducts photosynthesis in plant and algal cells. Chlorophyll is the photosynthetic pigment that absorbs the energy from sunlight. It then converts and stores this energy in the energy-storage molecules, ATP adenosine triphosphate and NADPH nicotinamide adenine dinucleotide phosphate. There are various parts within the structure of chloroplast, which include membrane envelope, intermembrane space, stroma, thylakoid system, grana, and chlorophyll. Grana and stroma are the two distinct regions present inside a chloroplast. The grana are the functional units of chloroplasts and consist of chlorophyll pigments. The stroma is an aqueous, alkaline and protein-rich fluid that contains various enzymes, ribosomes, DNA, and other substances present inside the chloroplast membrane surrounding the grana. This book includes some of the vital pieces of works being conducted across the world, on various topics related to the chloroplast. I