Chapter 11 addresses the task of designing computer tools for use in organizational contexts. We focus on the activity of people called 'managers,' but the same concerns arise in all situations involving social interaction and collaborative effort. Drawing on Heidegger's discussion of 'thrownness' and 'breakdown,' we conclude that models of rationalistic problem solving do not reflect how actions are really determined, and that programs based on such models are unlikely to prove successful. Nevertheless, there is a role for computer technology in support of managers and as aids in coping with the complex conversational structures generated within an organization. Much of the work that managers do is concerned with initiating, monitoring, and above all coordinating the networks of speech acts that constitute social action.