Summary: The first chapter demonstrates the importance of mobile peer-to-peer networks. Starting from the very first communication architectures, the evolution towards mobile peer-to-peer networks is described. Different forms of mobile peer-to-peer networking are explained by means of examples such as cooperative networking and social mobile networking. The chapter also gives an overview of existing and future wireless and mobile communication technologies, covering WiFi, Bluetooth in its current and future forms, and cellular systems such as UMTS, HSDPA, and WiMAX/LTE.