This chapter introduces the concept of information granules and processing of information granules. Information granules along with a faculty of their processing constitute an area of Granular Computing. The chapter presents an omnipresent visibility of information granules in the perception of real-world phenomena, coping with their complexity, and highlights a role of information granules in user-friendly schemes of interpretation of processing results and the design of intelligent systems. It elaborates a variety of formal methods used to describe information granules, and explores the underlying processing frame-work. The chapter presents a bird's-eye view of the associated formalisms and ensuing semantics of information granularity and information granules. The quantification of levels of belongingness to a given information granule is granular itself rather than numeric as encountered in sets or fuzzy sets. Information granules can embrace several granulation formalisms at the same time forming some hybrid models.