"Better inter-agency working" has been the oft-quoted remedy to many reviews of services to support vulnerable children and young people, and yet outside the realms of tightly focused specialist teams it seems to be very difficult to achieve. Georgina Glenny here reviews three case studies of interdisciplinary and inter-agency working to examine some of the reasons for the difficulties and some of the factors that contribute to success. Her findings suggest that, however "loose-knit" they are, members of children's services can work together effectively if they feel themselves to be part of a common project served by an inclusive communication system. In the successful case studies the "common project" was defined by an agreed central purpose to guide action within a defined geographical locality. Central to achieving this purpose was a carefully managed series of communication feedback loops to ensure good quality information was being shared at all levels. With this communication system in place the complex system of relationships and actions that resulted could be reflected upon and continually tweaked to ensure that "project purpose" was achieved or at least "worked towards" in a managed way.