The question of 'R&D specialisation' has emerged as an issue of debate on the research policy agenda. But what is this question and why should we bother with it? The question boils down to whether, for any given geographical-political entity, there are benefits to having R&D efforts concentrated (or specialised) in a limited number of thematic areas and, if so, whether (a) public funding of R&D should focus on these areas accordingly and (b) corporate R&D investment should be steered towards these areas through structural changes to the economy (and how to achieve this). To explore this question and examine its implications for policy, the Institute for Prospective Technological Studies, together with DG Research, organised a workshop in Barcelona on 30 June 2008. This report is an edited compilation of contributions submitted by participants at this event.