We can only truly understand the impact of the information age by looking at some of the applications that make use of our modern telecommunications networks. The Internet, email, video conferencing, mobile phones, home banking, distance learning, digital newspapers: these are just some of the many resources that we now use regularly and that have become part of our everyday lives.

These new technologies, together with the ease with which we can now travel from place to place, are already ushering in a new society, one based on mobility and the widespread consumption of information. In this new society, diversity is the norm: we can see it in our workplaces, in our neighbourhoods, in our towns and cities. Our lives are becoming more and more multi-ethnic and multi-cultural. The main difference between what is happening today and other equally great changes that have taken place throughout history, however, is that humanity now has the tools at its disposal for communicating all around the world. And that is why heterogeneity is here to stay.

The humble aim of this course is to provide the reader with a basic knowledge of today's telecommunications technologies that will enable her or him to make full use of the new telematic networks.

The authors