Social networks are platforms to share media, ideas, news, links or any kind of content between users and their neighbors, thus providing a perfect reflection of the structure and dynamics of the society. The recent advances in social media and the growing use of social networking tools have lead to explosive growth of information available over the Internet and created a need to better understand the underlying structure of the knowledge flow. Social Network Analysis focuses on analyzing the relationships within and between users/groups in order to model the interactions and includes assumptions about how best to describe and explain the social network. Social Network Analysis and understanding the dynamics of social networks have become popular research topics and a vast number of studies have been performed. This chapter provides definitions of the basic concepts of Social Network Analysis and briefly introduces the topics covered in the book.