Below are links to institutions that will give formal instruction with fully qualified instructors for clergy, laity, and children.
Books for Self-Learning:
If you’re interested in getting to know the basics of the Catholic/Christian faith, I’ll point to these publications to get started on your journey Fr. Thomas Joseph White’s book serves as a good Catechism for those wanting to take a more than general understanding: The Light of Christ: An Introduction to Catholicism. And of course, the well-known book written by Pope Benedict XVI Introduction to Christianity:
If you want to get better acquainted with Sacred Scripture, I’ll point you toward Ascension press’s The Great Adventure Catholic Bible that has the reader go through the general narrative of Salvation History and points to what particular books supplement the same time period. The translation is the Revised Standard Version Catholic Edition, which my go-to translation as it has a more literal rather than dynamic translation of the original texts.
In case you’re wanting a deeper study into the life of our Blessed Lord Jesus Christ, there’s no going wrong with Pope Benedict XVI’s Jesus of Nazareth biographies which led me to take my faith more seriously. Another great and time tested book is Ven. Fulton Sheen’s Life of Christ.
If you’re looking for a good Catechism for children, in my opinion, there’s nothing better than the true and tested Baltimore Catechism. It may be considered a bit dated with its rote learning set up, but what I’ve found lacking in modern religion textbooks is there is an assumption of general knowledge of the faith. The Baltimore Catechism builds that solid foundation. Furthermore, my experience with using this text in class is that children often do like the question and answer recitation especially if they’re tutoring comes after going to school all day.
For adults, the most accessible way to learn the faith is the Catechism of the Catholic Church: