The book in one paragraph
Lewis asks whether miracles can happen at all, and if so, whether any are believable. He first argues that a purely "Naturalist" picture of reality has a problem it can't escape (Ch. 2–6), then answers common objections (Ch. 7–13), and finally argues that the Christian miracles fit together around one central event, the Incarnation (Ch. 14–16).
The shape of the argument
Part 1Are miracles possible? Is Nature a closed system? Lewis says we can't assume so, and reason itself hints otherwise.
Part 2Would they happen? Would a God act in the world, and what would that look like?
Part 3Which ones are credible? Judge stories by evidence and by how well they fit the "Grand Miracle".
Your progress
Covers all 17 chapters plus both appendices. Read a chapter card, then take the quiz. Every answer explains the reasoning, not just the result.