This booklet describes the adolescent population of fourteen countries in terms of their demographic profile such as their poulation size, age of marriage, educational attainment, employment, and health, among others. This followed by an overall picture of the reproductive and sexual health characteristics of the adolescents through their fertility practices, teen pregnancy/childbearing abortion, HIV/AIDS and STDs, family planning and contraception. The last part synthesizes the different knowledge, attitude and practice (KAP) surveys dealing with the youth's sexual behaviour, knowledge, attitude and behaviour on sexuality, age at first intercourse, and incidence of pre-marital sexual activity. Booklet One thus sets the context, i.e. the problem that the adolescents face for which the succeeding two booklets address their focus on.