Cluster theory is simply a package of some of the recently discovered natural laws of chemistry. These laws have enabled us to analyze and categorize chemical clusters of one or more skeletal elements. Most importantly, it can help us determine whether a cluster is metallic, metalloid, or nonmetallic. Further, of this, we can also determine the number of skeletal bonds or linkages a cluster possesses and the number of cluster valence electrons within it. Most importantly, it enables determining the possible SYMMETRY OF THE CLUSTER. This book covers a wide range of chemical clusters such as the ordinary clusters (Conventional clusters), hydrocarbons, boranes, metalloboranes, carbonyl clusters, golden clusters and Zintl ion clusters just to mention a few.