The Catechism of the Catholic Church (CCC)
(Available in Chinese, English, French, Italian, Latin, Latvian, Malagasy, Portuguese and Spanish)
A summary of the teachings of the Church in faith and moral.
The Code of Canon Law
(Available in Chinese, English, French, German, Italian, Latin, Portuguese, Russian, Spanish)
Compendium Of The Social Doctrine Of The Church (English)
(Also available in Albanian, Byelorussian, Chinese, Dutch, English, French, Greek, Hungarian, Indonesian, Italian, Polish, Portuguese, Spanish, Swahili, Ukrainian, Vietnamese at the bottom of this page)