There’s a running joke in Canada about our charming sense of delicate hubris. A Toronto newspaper headline wryly proclaims: “Man Lands on Moon. Boots made in Montreal!” In other words, we’re only 30 million strong and we’re invariably mistaken for quiet Americans, and so when we do achieve something remarkable, even of a minimal variety, we like people to know.

Which is why the world needs to know that what will now be the standard life of Pope Pius XII—the definitive biography of the wartime pontiff at least for the present—has just appeared. And it was written by a Canadian academic. It’s true that Harvard University Press published the book, but Robert A. Ventresca is a professor at King’s College at Western University in...