This has been supplanted by edge computing, which represents a paradigmatic shift to a distributed model of computation, placing processing resources close to data sources and the end consumer, rather than in a centralised cloud architecture. This chapter presents an in-depth examination of the principle of edge computing, its architecture and applications, exploring the technological builds, security issues, and emerging trends that characterise this essential computing principle. We examine the reasons that encourage the adoption of edges, examine the various classes of devices and architecture, and examine applications throughout Internet of Things (IoT), autonomous systems, and artificial intelligence. It also analyses the frameworks of security and privacy needed in a distributed computing context, discussion of the emerging patterns such as edge-native AI, and integration of 5G and considerations around sustainability. The chapter provides to the realisation of pacification and forward-looking projection of future perspectives on the functions of edge computing in the context of contemporary distributed systems, through consistent assessment of the capabilities and directions.