Karl Keating is founder and president of Catholic Answers, the country’s largest apologetics and evangelization organization. He is the author of five books, including Catholicism and Fundamentalism and What Catholics Really Believe.
Memorize the Faith! By the time you finish this book, you will have memorized dozens of key teachings of the Church, along with hundreds of precepts, traditions, theological terms, Scripture verses, and other elements of the Faith that every good Catholic needs to know by heart
"The gravest obligation requires the acceptance and practice, not of the religion which one may choose, but of that which God prescribes and which is known by certain and indubitable marks to be the only true one."
~ Leo XIII in his Encyclical Immortale Dei (November 1, 1885); on our fundamenal duty; (from the article Religious Toleration)