Coordination, and the communication it implies, is central to the very existence of organizations. Despite their fundamental role in the purpose of organizations, scholars have little understanding of actual interaction patterns in modern, complex, multiunit firms. To open the proverbial "black box" and begin to reveal the internal wiring of the firm, this paper presents a detailed, descriptive analysis of the network of communications among members of a large, structurally, functionally, geographically, and strategically diverse firm.