The field of cluster sciences is currently attracting considerable interest, not only from a fundamental viewpoint but also in relation to future applications to electronic, optical and magnetic devices. Synthesizing specific clusters as a component of useful nanostructures or controlling them as an assembly of nanocomposites is the ultimate aim. In order to understand how to synthesize individual clusters or to investigate properties such as chemical reaction, structural stability, response to external fields, aggregation and phase transitions, a variety of first-principles and empirical calculations and related computer simulations have been performed alongside numerous experiments. This book compiles and collates recent theoretical and experimental advances in the field and demonstrates how the harmony between theory and experiment is contributing to the continuing rapid progress. It will be of interest not only to researchers, but also to students and newcomers seeking a review of the present status.