Well, 'The Shack' is a well - known life changing Christian fiction book. It presents a unique view of the Trinity and how God interacts with people in times of great pain. 'Left Behind' series by Tim LaHaye and Jerry B. Jenkins is also quite influential. It focuses on the end times and what it means to be a Christian during those events. And 'Hinds' Feet on High Places' by Hannah Hurnard, which is about a journey of spiritual growth and transformation.
One of the great life changing Christian fiction books is 'The Pilgrim's Progress' by John Bunyan. It's a classic that uses an allegorical journey to represent a Christian's spiritual journey. Another is 'Redeeming Love' by Francine Rivers. It retells the story of Hosea in a historical fiction setting, showing God's unconditional love in a very powerful way. Also, 'This Present Darkness' by Frank Peretti is impactful as it gives a fictional look at spiritual warfare.