I love to read detailed conversion stories, especially when they come from (formerly) committed atheists like Guillaume, and especially when they arise out of thoroughly secular environments like the nation of France. As Guillaume tells his life story, he weaves in the occasions on which he was led to explore all of the major objections to the Christian faith (science, certainty, evolution, reliability of the Gospels, miracles, etc), and how his questions were satisfactorily answered. The writing style can be pretty simplistic sometimes, especially when personal anecdotes are related, but I think this works in Guillaume’s favor, because before long you find yourself grappling with some pretty sophisticated philosophical concepts, but only briefly, because Guillaume’s life story is the main thrust of the book. This book would be a very appropriate gift for your atheist or skeptical friend.