If you’re looking for a truly fulfilling use of your time, these books, DVDs or audio CDs are highly recommended. Of particular importance are the Holy Bible and the Catechism. The whole of what we believe and why we believe as we do can be found in these two incredibly powerful books. Pope John Paul II states in his forward in The Catechism of the Catholic Church that this catechism is “offered to all the faithful who wish to deepen their knowledge of the unfathomable riches of salvation (cf. Eph 3:8)."
The Holy Bible
Catechism of the Catholic Church
United States Catholic Catechism for Adults
YouCat: Youth Catechism of the Catholic Church