E ach edition of the Handbook of Organizational Communication has contained a chapter on communication networks. In the first edition, Monge and Eisenberg (1987) reviewed literature on the antecedents and outcomes of communication networks. In the second edition, Monge and Contractor (2001) reviewed ten families of theories that explained the emergence of communication networks. The third edition of the Handbook of Organizational Communication reenvisions the study of communication networks, beginning with its definition. In the second edition, Monge and Contractor (2001) define communication networks as “the patterns of contact between communication partners that are created by transmitting and exchanging messages through time and space”(p. 440). Although patterns of contact are a type of communication network, the current chapter expands the scope of this definition. In particular, we define communication networks as relations among various types of actors that illustrate the ways in which messages are transmitted, exchanged, or interpreted. This definition extends the previous one in three important ways. First, it includes multidimensional networks (Contractor, 2009; Contractor, Monge, & Leonardi, 2011) that are composed of a variety of types of actors including, but not limited to, individuals, groups, organizations, artifacts, concepts, and technologies. Second, the definition highlights that communication networks are multiplex, meaning that it is useful to simultaneously consider multiple types of relations. Finally, it suggests that networks capture communication processes that are more complex than message exchange.

This chapter focuses on the various types of relations that constitute multidimensional communication networks. As such, it provides an important alternative to other ways in which the literature has been reviewed (Borgatti & Foster, 2003; Krackhardt & Bass, 1994; Monge & Contractor, 2001; Monge & Eisenberg, 1987). We begin with an overview of multidimensional networks and their importance for organizational communication research. The core of the