This book describes data centric networking in distributed systems, which relies on content addressing instead of host addressing, thus providing network independence for applications. Recent progress in wireless sensor networks requires such a data-centric approach, where sensors are used to gather high volumes of different data types to feed as contexts to a wide range of applications. Publish/subscribe asynchronous group communication realises the vision of data-centric networking that is particularly important for networks supporting mobile clients over heterogeneous wireless networks. In such networks, client applications prefer to receive specific data, which requires selective data dissemination. Underlying mechanisms such as asynchronous message passing, distributed message filtering and query/subscription management are essential. The book demonstrates solutions for challenging topics ranging from event and query modelling using hypercube, publish/subscribe by context adaptive controlled flooding, to event correlation semantics, providing the design aid for distributed ubiquitous computing systems over heterogeneous networks.