Catechism of the Council of Trent
The Catechism of the Council of Trent, also called the Roman Catechism or the Catechism of St. Pius V, is universally recognized as the most authoritative Catechism ever written. It has been praised by Popes, theologians, cardinals, and saints. It was ordered by the Council of Trent, edited under St. Charles Borromeo, and published by decree of St. Pius V. Pope Leo XIII recommended two books for all seminarians - St. Thomas Aquinas' Summa Theologica and the Catechism of the Council of Trent.
Click here for the traditional teaching of the Church