This book explores the role of surface effects in optical phenomena in nanoscience, from two different perspectives. When systems are reduced in volume, the ratio of surface versus volume increases. At the level of single nanostructures this translates into an enhanced role of interfacial chemistry and thermodynamics. At the level of systems of nanostructures, it translates into larger density on interfaces, which in turn leads to such intriguing collective effects as plasmonics or multiple reflection and refraction phenomena. The book highlights both perspectives presenting sample applications. Without claiming to be exhaustive, the book aims to stimulate readers in this potentially rewarding field.