Don't be fooled by the title, Armand is an apologist pretending to be a neutral moderator for a debate in which he speaks for both sides, & it is all too clear which side he is on. The book isn't so much of a debate as it is a biography, or rather 2 bios laced together. One is a celebration of the life & conversion of Lewis, the other a criticism of Freud & everything he stood for.
This book does not deal with evidence, for or against God or Christianity, outside of the positive effects belief has had on converts like Lewis, & the gloomy negativity of Freud's atheistic worldview. Armand may as well tell we should just accept Lewis' view bc Freud's is too depressing. I'll tell you what's depressing, this book & the way it portrays atheism. Belief in God certainly has a stronger emotional appeal, but that doesn't make it true, nor superior. Religion does not have a monopoly on joy or meaning. It may have helped Lewis get through some hard times, it may have improved his life... good for him, doesn't make him right. Life is hard, but everyone can't just make themselves believe in order to feel better, & we certainly don't need people like Armand trying to convince us unbelievers that we have nothing to live for.
As for Lewis, though I admire him as writer, I can't help but find his arguments weak & even fallacious. I'm not saying he was a liar, & he was certainly no fool, but he was only human after all. Jesus, on the other hand, couldn't have been any of the 3, at least not according to Lewis. This famous trilema leaves out the possibility of legend, despite it's obvious alliterative value, bc Lewis can't see the gospels as fitting into the myth & legend genre. That's odd, since later he admits that all the myths he studied have the same theme of death, redemption, & resurrection. Lewis argues that these were only foreshadowings of real deal. This reminds me of Justin Martyr's claim that Satan, knowing the future, sent counterfeits of Christ in advance. So the later stories about a dying & rising god-man were the true ones on which the preceding myths were based? Got it. I suppose Socrates was plagiarizing Paul when he said things like "to die is gain" & Confucius was ripping off Jesus with his "do not do to others what you wouldn't want them to do to you." I'm sorry, but brilliant as he was, Lewis was thinking with his heart & not his brain, when he wrote about his faith.