"This book is a must-read for the new generation of interdisciplinary researchers. World-class scientists join in debating the causes of a broad class of problem behaviours, from the role of environments in gene expression to new preventions and policy implications. This research has profoundly changed our views on the nature of aggression."- Raner K. Silbereisen, Chair of Developmental Psychology and Director of the Center for Applied Developmental Science, University of Jena, Germany