In the genes of all social animals, mutual support is recognizable as much in chimpanzees that tickle each other as in children who build sandcastle or men and women who hoard sacks of earth to ward off a sudden flood: all cooperate to accomplish what they can not do alone. This natural, innate tendency is less a genetic trait than an art, a social capacity, which requires a ritual to develop. In a world structured by competition, where competition always prevails over understanding, do we still know what it is to be together, beyond the tribal fold of "us-against-them"? In this second part of the trilogy he devotes to homo faber, Richard Sennett, is a historian, sociologist, philosopher or anthropologist to study this particular social asset that is cooperation in practical work. From the coordination of the tasks in the printer's workshop to the rehearsals of an orchestra, he introduces us to many experiences of community and collective action that allow us to propose a critical vision of contemporary capitalist societies. The richness of the references, the originality of the points of view, the freedom of the style and the will to remain always at the level of the daily experience make the strength of this singular and committed book. And if, to get out of the crisis, it was enough to relearn to cooperate?