Need is a popular but controversial concept in social policy. 'Needs-led' has become a mantra in children's services in recent years, yet theorists still argue about the meaning and value of the concept of 'need'. There are lots of needs assessment at the individual child and population levels, but case files vary enormously in quality and reports of need analyses frequently gather dust on shelves. How, then, should we define and measure children's needs, and how should this influence the design of services? This edited collection answers these questions in order to help policy makers, managers, practitioners and researchers with identifying and serving children in need. It offers a critical appraisal of the state of play regarding the theory of need, the needs that children have, methods for assessing children's needs at the individual and group levels, and approaches to designing services to meet identified needs.