Internet-based communications have amazingly evolved in recent years. As a consequence, the number ? and complexity ? of distributed systems which provide access to services and applications has dramatically increased. As long as these services have been extended to support an increasing number of communication media (voice, audio, video, ...) and systems, ad hoc communication protocols and methodologies have been designed and developed. Given the autonomy of available services and applications, distributed systems generally rely on event-based communications for integrating these resources. However, a general model for the management of event-based communications, suitable for complex and ad hoc event processing as well as for the generic publish/subscribe messaging paradigm, is still missing. This paper presents1 a general and flexible event detection and processing framework which can be adapted based on specific requirements and situations. Within the framework, the main aspects of event management over distributed systems are treated, such as event definition, detection, production, notification and history management. Other aspects such as event composition, are also discussed. The goal of the paper is to provide a common paradigm for event-based communications, providing at the same time new advantages with respect to the existing standards such as composition, interoperability and dynamic adaptability.