Is cooperation against human nature? That would be sad news, in particular for the Coordination Action ENCORA, which aims to promote and facilitate sharing of knowledge and experience among coastal professionals in Europe. “Critical Mass”, the recent bestseller of Philip Ball, former journalist of Nature, is a fascinating account of new insight in the often surprising outcome of interaction processes among people. He shows how social behaviour and cooperation may result from interaction processes among people, who individually seek to optimise personal interest. However, beware of simple rules, is one of the messages, because social interaction processes have a strong stochastic or chaotic component and depend on spatial and temporal scales. Instead of giving thumb rules, Critical Mass provides inspiring thoughts on social organisation and valuable understanding for everyone who is involved in broad cooperation initiatives.