There are many communities involved in the creation of cyber-physical systems, which are used in domains including transport, health, manufacturing and, in the longer term, will be in the home, where miniaturization will play a role. In this article we explain that engineering for future CPS needs a centre of gravity that has the purpose of drawing these communities together. This will provide common goals around which technical advances can be aligned. Overviews of the communities involved are provided, with examples of their relevance to build CPS and to some common challenges. Advancements of aggregating technologies are multi-dimensional challenges, representing many influencing dependencies from all communities, especially at higher levels where the whole system product is drawn together. This means that, to make good progress, Europe will require higher levels of coordination for research orchestration and for capitalizing on lessons learned in relation to the cumulative advances among the communities.