In this book, we try to find a connection between rough sets, fuzzy sets and Topology.Although there are differences among these theories of granular computing in their formulation, i.e., construction of granules and representation of their relationships, their core idea is the same. That is, a problem space is firstly divided into some basic granules. Then, these basic granules are further composed or decomposed into new granules at Different hierarchies. The above two steps are repeated until these new granules could solve the problem more valid.