This book deals with the implementation and application of the "in the best interests of the child principle" in research and practice. With contributions by authors from nine different countries (United States, Belgium, France, Norway, The Netherlands, United Kingdom, Israel, Ireland, Canada) an international perspective is adopted. An outline of the theme is given in the introductory chapter. The main part of the book consists of three parts. The first part contains three chapters illustrating the search for theory-driven and empirically-based models to deal with the complexity of parenting. In the second part which contains five chapters, illustrations about the implementation and application of the best interests principle in child and youth care practice are given. Part three (four chapters) is focusing on the organization of child and youth care systems according to the best interests principle.