The basic proposal in this book is the need to provide children and young people with support as they cope with critical family change resulting from serious parental conflict and separation. The overall aim is to encourage policy makers, politicians and law reformers to develop coordinated preventive early intervention, policies and practice in the fields of education, family justice and mental health. These should seek to reduce adverse impact on children's educational performance and reduce the risks that some youngsters will develop long-term more deep-rooted behavioural and mental health problems. The purpose, therefore, of this first part is to convey some idea of the numbers of those potentially at risk and to review educational and behavioural science research which highlights the adverse effects of acrimonious interparental conflict and separation on children's educational and psychological development and wellbeing. This helps to prepare the background for certain policy and practice proposals which I set out in my conclusions (Chapter Thirteen) concerning short-term crisis intervention programmes in schools and, as a backup, in the context of the interdisciplinary family justice regime now operating the new Child Arrangements Programme in family courts.