YOUCAT: Youth Catechism of the Catholic Church
"YOUCAT is the Catechism of the Catholic Churches for adolescents and young people. The most important contents of the faith are summarized briefly and comprehensibly in the format of questions and answers. The YOUCAT was approved by the Congregation for the Doctrine of the Faith in Rome and officially published by the Austrian Bishops' Conference. With more than 5 million sold copies, it is one of the best-selling Catholic books in the world."