Wow, Isaiah, there are so many! Maybe I’ll start with a few that I read early on in my walk with Christ that had a formative influence:
Knowing God, by J I Packer (especially what Packer says about God adopting us into his family – so important!)
Fox’s Book of Martyrs (yes, that was one of the first books I read cover-to-cover as a new believer – aged 19 or 20 – and it helped me to see that any cost we might have to pay in order to follow Christ is worth it!)
Battle for the Bible, by Harold Lindsell (this established in my mind how central the role and authority of Scripture is in the life of the believer and in the health and future of ministries and churches. I think many of the battles that are being fought today are ultimately about the question of the Bible’s authority. Will we accept what God tells us about morality, the value and meaning of life, marriage, etc.? The answer from far too many is “no” — but we need to be those who say a resounding “yes”!!
More Than a Carpenter, by Josh McDowell; now in a newer edition by Josh and Sean McDowell (this was probably my first introduction to historical apologetics, and it was a good one. MANY have come to faith in Christ through this potent little book!)
Mere Christianity, by C S Lewis (in some ways so simple, yet simultaneously so brilliant!)
I’ll mention one more – one that I think should be required reading for every person on the planet:
The Case for Christ, by Lee Strobel (yes, Lee is my close friend and ministry partner, and yes I was involved in shaping the book – but it’s an absolute classic, and it has been and continues to be a powerful tool for reaching people who are resisting the gospel, as well as a fantastic training tool for believers. I’ve given away countless copies myself, and have met hundreds of people who have trusted in Christ after reading it). I should also add that the newest edition of C4C includes a new chapter at the end of the book in which I interview Lee and have him share some of the most unique and exciting examples of how God has used the book.
Many more could be listed, but those are some of the earlier (other than C4C) and more influential books in my life. I’ll simply add that one of the most important disciplines for every believer is to be constantly reading (or listening to) a great Christian book. I think a good goal for most people would be to read at least one book per month (but more than that will increase learning more quickly! : ).