The apostolic constitution by which John Paul II promulgated the Catechism of the Catholic Church, published on the thirtieth anniversary of the opening of the Second Vatican Council. It recounts the 1985 Extraordinary Synod's request for a compendium of doctrine, the six years of work by the commission of cardinals and bishops and the worldwide consultation of the episcopate, and explains the Catechism's four-part structure. It declares the Catechism a sure norm for teaching the faith and a valid and legitimate instrument for ecclesial communion, offered to the pastors and faithful of the whole Church.