Comprehensive theoretical and experimental analysis of UV-radiation and low energy electron induced phenomena in nucleic acid bases (NABs) and base assemblies are presented in this book. NABs are highly photostable; the absorbed energy is dissipated in the form of ultrafast nonradiative decay. This book highlights the possible mechanisms of these phenomena which is important for all living species and discusses technical challenges in exploration of these processes. This volume will be of particular interest for those involved in understanding the photophysical/photochemical properties of nucleic acids. All chapters are written by the world's leading experts, both from the experimental and computational areas.