Abstract. In this paper we describe an approach to the representation and implementation of agent-based systems where the behaviour of an individual agent is represented by a set of logical rules in a particular form. This not only provides a logical specificationof the agent,but also allows us to directly executethe rules in order to implement the agent's behaviour. Agents communicate with each other through a simple, and logically well-founded, broadcast communication mechanism. In addition, agents can be grouped together. This not only restricts the extent of broadcast messages, but also provides a structuring mechanism within the agent space. The purpose of this paper is threefold: to motivate the use of our particular computational model; to show that a logic-based approach is both possible and potentially very powerful; and to assert that by narrowing the gap between the agent theory and the agent programming language, we are able to bring the prospect of formal specificatio...