Why does everybody call for high speed mobile data ? What are the different technologies to achieve higher throughput rates in a mobile network? What are the risks and hazards of high speed mobile data ? This chapter will provide you first an introduction to the commercial aspects of high speed mobile data before we talk about HSCSD, GPRS and EDGE. You will obtain a basic understanding of the concepts, principles, differences and network infrastructure of HSCSD, GPRS and EDGE.