This research monograph examines the difficulties of gathering and expressing requirements for agent based systems, and describes the development of an agent oriented requirements elicitation framework. Conceptual modelling in the form of Conceptual Graphs is offered as a means of representing the constituent parts of an agent based system. In particular, use of a specific graph, the Transaction Model, illustrates how complex agent concepts can be modelled and tested prior to detailed design specification. Using an exemplar in the healthcare domain, a design framework is developed showing how the Transaction Agent Modelling (TrAM) approach assisted the design of complex community healthcare payment models. Insight gained during the design process is used to enrich and refine the framework in order that detailed ontological specifications can be constructed, before validating with a mobile learning scenario. The ensuing discussion evaluates how useful the approach is, and demonstrates a number of significant contributions for early requirements gathering in Agent Oriented Software Engineering (AOSE).