While the chemistry, physics, and optical properties of simple atoms and molecules are quite well understood, this book demonstrates that there is much to be learned about the optics of nanomaterials. Through comparative analysis of the size-dependent optical response from nanomaterials, it is shown that although strides have been made in computational chemistry and physics, bridging length scales from nano to macro remains a major challenge. Organic, molecular, polymer, and biological systems are shown to be potentially useful models for assembly. Our progress in understanding the optical properties of biological nanomaterials is important driving force for a variety of applications.