Before Lewis embraced the Christian faith he had a lengthy debate with one of his friends, Owen Barfield about what would be considered involving subtle metaphysical and philosophical distinctions. It became know as the "Great War." These disagreements impacted Lewis a lot, but this topic isn't often explored with much detail in biographies. Joy and Poetic Imagination: Understanding C. S. Lewis's "Great War" with Owen Barfield and its Significance for Lewis's Conversion and Writings is a book by Dr. Stephen Thorson that examines the issue thoroughly. The following podcast is a brief interview with Stephen as well as a short talk he gave at the 2016 Taylor Colloquium.