Adolescence is the critical period or rather process in human development, where the individual leaves the dependency of childhood and enters a period in which dramatic changes occur, eventually resulting in what society identifies as adulthood. It is a complex developmental time involving sociological, psychological and physiological issues that starts with puberty and ends sometime in the third decade of life with central nervous system maturation (parents would want this period to be much quicker and shorter). The goal of adolescence is to develop an autonomous adult, who is capable of functioning at intellectual, sexual, and vocational levels acceptable to society. Prevention and management of health problems in children and adolescents can prevent considerable morbidity in adults. Working with adolescents is difficult, frustrating and very rewarding at the same time. In this book, we have gathered international research to show you a picture of health issues in adolescence and during the school period of human development.