Abstract: Autonomous objects is a new computing and coordination paradigm for distributed systems, based on the concept of intelligent messages that carry their own behavior and that propagate autonomously through the underlying computational network. We survey and classify several existing systems that fall into this general category of autonomous objects and present a unifying view of the paradigm by describing the principles of a high-level language and its interpreter, suitable to express the behaviors of complex autonomous objects, called Messengers. We discuss the capabilities and applications of this paradigm by presenting solutions to several distributed computing problems. This includes problems in network control and in dynamic composition of inherently open-ended applications, such as interactive simulations, where it is not possible to define and precompile the entire experiment prior to starting its execution.