national audience if the active participation of customers in the delivery of a service has been accurately observed by sociologists for some 30 years, it now seems to be gaining a new scale. Customer activity is now required for an increasing number of physical services and goods. And for each of them, it extends to new tasks. By becoming more widespread and changing its nature, co-production is no longer a phenomenon on the margins of organisations. Is it a specific production method? A new division of labour? Can we go so far as to talk about putting clients into work? These are the issues addressed by this issue, which, in a multidisciplinary approach and through a variety of cases, describes the activity of clients in various economic sectors. Authors examine the conditions for their participation in the production and social construction of the market. If they then describe the framing, monitoring and prescribing arrangements aimed at ensuring that customers carry out specific tasks, the articles also show the initiatives taken by them to take advantage of, model or escape the market.