This book focusses on basic science, but it also addresses engineers interested in new materials. Experiments on metal clusters are reviewed in two long pedagogically written articles. The theoretical courses cover three main domains: (1) electronic properties of metallic clusters and nanostructures, (2) phases and phase changes of small systems, and (3) chemical processes in nanoscale systems. Furthermore, interested readers, researchers as well as graduate students will find articles on density functional theory, magnetic properties of clusters, and computer simulations of cluster dynamics. In addition, the book addresses chemical processes, pairing correlation effects and also biological systems.