This book provides an introduction to System Architecture Evolution (SAE) standardization work and its main outcome; the Evolved Packet Core (EPC), including potential services and operational scenarios. The book gives explanations of the EPC architecture and concepts as an introduction. In technical descriptions of EPC follow, including functional accounts of the different components of EPC, protocols, network entities and procedures. Case studies of deployment scenarios show how the functions described within EPC are placed within a live network context, while a description of the services that are predicted to be used shows what EPC as a core network can enable.