In the following, we briefly characterise the EAGLES project, then present the background to EAGLES. We describe the motivation for the project and explain its underlying basic concepts, its objectives and foreseen impact. We also include a short section to place EAGLES in its historical perspective both to emphasise the long-term nature of this type of work and to acknowledge the invaluable efforts that have taken place over the years which have helped give rise to, and determine the nature and form of, the EAGLES project.