In what way is "care" a matter of "tinkering"? Rather than presenting care as a (preferably "warm") relation between human beings, the various contributions to the volume give the material world (usually cast as "cold") a prominent place in their analysis. Thus, this book does not continue to oppose care and technology, but contributes to rethinking both in such a way that they can be analysed together. Technology is not cast as a functional tool, easy to control - it is shifting, changing, surprising and adaptable. In care practices all "things" are (and have to be) tinkered with persistently. Knowledge is fluid, too. Rather than a set of general rules, the knowledges (in the plural) relevant to care practices are as adaptable and in need of adaptation as the technologies, the bodies, the people, and the daily lives involved.