While tactical command. control and communication environments might appear to be entirely instrumental in nature, they nevertheless provide a setting for social interaction. This paper describes how such interaction occurs in a particular naval tactical command and control system, focusing on the shared perspectives created by the organizational, administrative and professional aspects of the environment and on issues of self-presentation. It is argued that the complexity and multiplicity of interactional regions in this environment lead to problematic situations for key actors, and that these problems may have relevance to future computing environments. Author Keywords Command, control and communication; tactical data systems; social worlds; self-presentation. ACM Classification Keywords H.5.3. Group and Organization Interfaces: Computersupported cooperative work.