An object-oriented computation model is presented which is designed for modelling and describing a wide variety of concurrent systems. In this model, three types of message passing are incorporated. An overview of a programming language called ABCL/1, whose semantics faithfully reflects this computation model, is also presented. Using ABCL/1, a simple scheme of distributed problem solving is illustrated. Furthermore, we discuss the reply destination mechanism and its applications. A distributed “same fringe” algorithm is presented as an illustration of both the reply destination mechanism and the future type message passing which is one of the three message passing types in our computation model.