This definitive textbook provides accessible information on best practice for assessing the needs and strengths of vulnerable children and their families. It explores the challenges that practitioners face routinely - with suggestions as to how to address them - as well as the established areas for assessment, of children's developmental needs, parenting ability and motivation, and socio-economic factors. This new edition has been extended substantially to include recent practice, policy and theoretical developments, such as understanding the lived experience of children, young people, and family members. It also considers children's neurological development, assessing parental capacity to change, early help assessments, emerging areas of practice such as child sexual exploitation, and working with asylum-seeking and trafficked children. Crucially, this updated edition takes a broader approach in offering relevant information to a range of professionals working with vulnerable children. The importance of inter-professional working is emphasised throughout.