Formal methods of generating and specifying requirements have a chequered past when it comes to dealing with interface design. The Human Computer Interface (HCI) community have not adopted formal methods with open arms [Paterno 96]. If the accurate determination of stakeholder requirements is a significant factor in determining software project success, this thesis turns to a theory based in psychology and sociology to understand these capricious actors, the misunderstanding of whose whims can bring down 70% of software projects. This thesis will deploy Activity Theory as a basis for a proposed system design method and present initial conceptions and some preliminary case-study findings in support. It is anticipated that such a method could bring significant benefits, especially to a particular and growing class of projects; those whose functionality relies heavily upon user interaction.