This book is published in order to raise world-wide medical awareness about the nature of bullying and its link to serious health risks. It highlights the global occurrence of this type of maltreatment, which has been found to jeopardise the lives of millions of young people around the world, who either bullied others and/or were victimised themselves. These groups of young people are at higher risk, than their cohorts, for three leading proximate causes of death, such as accidents, suicide and homicide. Furthermore, they have a greater risk of non-proximate lethal aetiologies including daily smoking, alcohol abuse, carrying and using weapons, eating disorders and running away episodes. This book is based upon two special issues published in the International Journal of Adolescent Medicine and Health and permission has been obtained from the publisher De Gruyter in Berlin to publish this modified and updated version of the papers in this book.