ame common. The Royal Mail of the Persian Empire was an advanced form of such a telecommunications system. Security and trade have continued to remain a major reason for the development and main- tenance of telecommunications infrastructure. Increasingly trade, for example across the Silk Introduction Road, required a reliable messaging system. In contrast with the internal security-focused telecommunications systems, such as that of the Royal Mail, many of these trade-focused communications were across 'national' boundaries. It should be noted that the benefits of this telecommunications system were experienced by all and not just the senders and receivers. The society at large benefits from improved security, enhanced efficiency of trade and SO on. Very few telecommunications technology advances are recorded until the late 18th century and the development of Visual Telegraphy by Claude Chappe in 1794 (see Historical Note in Chapter2). This development owed its existence to a number of advances including architecture and building construction technologies and the invention of optical telescopes. It also depended on social/policy developments such as re-emergence of strong central governance or 'empire' which could build and benefit from a telecommunications infrastructure. The discoveries of electricity and electromagnetic field in the 19th century were further theoretical foundations which led to the invention of electrical telegraphy and telephony and the modern systems we use today. Some 2500 years after the Royal Mail was constructed and operated by the Persian Empire, many governments around the world are making decisions on how to build, and to what extent fund, their national telecommunications infrastructure. Again, construction and operating costs of a telecommunications system are weighed against business and strategic benefits of a national robust infrastructure which benefits most if not all of society. From a government policy point of view, telecommunications is a public need as well as a tool for 