Like a lot of titles, it pretty much cuts to the chase. It's a biography, it's about a boy, so… This Boy's Life seems a tad on the nose. It seems to suggest that there's something special about this boy, something different that we wouldn't see in other boys. But it also plays into a sense of the universal. All men were once boys after all, and "This" suggests that there's other boys who have lives as well. It brings up good question: why should we care about "this" boy? What's cool about him that wouldn't be with "that" boy or "the other" boy? All we have to do is open the book and find out.