“…only the scent of a flower we have not found, the echo of a tune we have not heard, news from a country we have never visited.” Nothing kidnaps our capacity for presence more cruelly than longing. And yet longing is also the most powerful creative force we know: Out of our longing for meaning came all of art; out of our longing for truth all of science; out of our longing for love the very fact of life. We may give this undertone of being different names — Susan Cain calls it “the bittersweet” and Portuguese has the lovely word saudade : the vague, constant longing for something or someone beyond the horizon of reality — but we recognize it in our marrow, in the strata of the soul beyond the reach of words. No one has explored the paradoxical nature of longing more sensitively than the philosopher, storyteller, beloved Narnia creator, and modern mystic C.S.…