Grab Your Bible & Check Out: The Catechism of the Catholic Church: Second Edition
I own well over 50 books related to Catholicism. I'm not listing all of them here, but do plan to continue to add to this page. Obviously the most important book you need is the BIBLE. Yes, contrary to popular belief, Catholics do read the BIBLE.
Immediately below are books that you can read / reference / search online without having to buy or download:
If you want to really dive in, use the Catechism below along with your Bible to go in depth.
Catechism of the Catholic Church: Second Edition
Catholic Answers to Protestant Questions: The Concise Summa of Catholic Apologetics
The Catholicism Answer Book: The 300 Most Frequently Asked Questions
In case you don't already know this, the Catholic Old Testament includes 7 books that are not in the Protestant Bible. Oh, and the books were "NOT" added by the Catholic Church at The Council of Trent in 1546 after Martin Luther started the reformation. The books were simply reaffirmed. It's easy to do some research on "The Council of Hippo" and "The Council of Carthage" back in the 390's and quickly learn the truth ( see this ). The Bible, as we know it, did not just magically appear one day as 66 books ( Protestant Bible ) or 73 books ( Catholic Bible ) - ( see Where We Got the Bible: Our Debt to the Catholic Church by Reverend Henry G. Graham ).
After the Bible, if you are a Catholic or you simply want to know what the Catholic Church "actually teaches" not what some people think the church teaches or twist words into saying things that are not accurate like "Catholics WORSHIP Mary," you should get a good, comprehensive copy of the "Catechism Of The Catholic Church."
The next two books are very popular. Be sure to search Amazon for "Dr. Scott Hahn" and "Karl Keating" to see numerous other books.
The very first book that I read cover to cover in my Catholic journey was "The Protestant's Dilemma: How the Reformation's Shocking Consequences Point to the Truth of Catholicism." I placed the order on Amazon on Christmas Day 2016. I started reading it on January 1st, 2017. Yes, I enjoyed the book, but NO, I was ready to become a Catholic after reading it. However, I did attend my very first MASS with my wife Brenda on Saturday, January 21st, 2017 at Sacred Heart Cathedral in Downtown Raleigh, North Carolina.
If you are considering converted to Catholicism, are considering leaving Catholicism ( hope not ) or have left Catholicism and are considering returning to the Church ( hope so ), the "Surprised By Truth" books by Patrick Madrid should be a blessing. In my own Catholic journey, I have found all the stories that I have read to be helpful.
Book 1 - Surprised By Truth: 11 Converts Give the Biblical and Historical Reasons for Becoming Catholic
Book 2 - Surprised by Truth 2: 15 Men and Women Give the Biblical and Historical Reasons For Becoming Catholic. (v. 2)
Book 3 - Surprised by Truth 3: 10 More Converts Explain the Biblical and Historical Reasons for Becoming Catholic (v. 3)
A Few Authors To Look Into:
Dr. Scott Hahn, Stephen K. Ray, Trent Horn, Tim Staples, Jimmy Akin, Karl Keating, Patrick Madrid, Devin Rose, Reverend Henry G. Graham and Cardinal John Henry Newman.