Mobile systems - primarily cellular telephony - have been the fastest moving telecommunications development to date with a world-wide customer base that in the ten or so years to April 1996 reached 100 million and continues with a current growth rate of 60% per annum world-wide. Predictions suggest that the customer base will exceed 1 billion within the next ten years and that the saturation level is around 80% of any population. Faced with such statistics any book such as this can proffer little more than a snapshot of the activities and developments that are at present taking place within the mobile world. It can, however, reflect on some of the underlying principles that support the industry. The opening chapter offers a vision for the future of mobile communications - that of more mobile than fixed connections to the world's telecommunica­ tions networks - one which, interestingly, pre-dates the emergence of the information superhighway. The Internet whose growth of computer networks has, in recent years, exceeded that of even mobile systems is demanding ever more bandwidth to support its multimedia applications and access for people on the move. The communications needs of the next century customer are the driv­ ers behind the convergence of computing and telecommunications networks, the mobile component of which will be realized as Third Generation Mobile Sys­ tems (fGMS).