Event-based systems are rapidly gaining importance in many application domains ranging from real time monitoring systems in production, logistics and networking to complex event processing in finance and security. The event based paradigm has gathered momentum as witnessed by current efforts in areas including publish/subscribe systems, event-driven architectures, complex event processing, business process management and modelling, Grid computing, Web services notifications, information dissemination, event stream processing, and message-oriented middleware. The various communities dealing with event based systems have made progress in different aspects of the problem. The DEBS conference attempts to bring together researchers and practitioners active in the various sub communities to share their views and reach a common understanding.