You don’t need to know anything about the history of architecture to appreciate medieval cathedrals. They stand, worthy of regard, as independent works of art. But dig into the history of the cathedral, into the intention and design of the architects, and vistas of appreciation open for you. Medieval philosophy about light, proportion, number, and symbology permeate the cathedral structure, rendering it a building full of grander theological meaning than what is apparent to the uninformed observer. Like the cathedral, C.S. Lewis’s Narnia books stand on their own with independent merit and beauty. In fact, until now, they have seemed to stand with a kind of strangely haphazard unity—all the books are about Narnia and Aslan, but little else seems to hold them together. Countless readers have appreciated them this way without troubling themselves too greatly over the organization of the septet. But now Michael Ward in his book Planet Narnia has uncovered what amounts to Lewis’s architectural drawings for the Narnia books, exposing a hidden organization to these beloved stories.

What is that hidden organization? C.S. Lewis, medieval scholar that he was, designed each of the Narnia books in the image of one of the seven medieval planets: Jupiter, Mars, Sol (the sun), Luna (the moon), Mercury, Venus, and Saturn. Far from being a haphazard collection of children’s books, the seven Narnia volumes instead are meditations on the seven medieval planets, built upon a highly sophisticated architectural substructure. Under Lewis’s guidance the characteristics and ethics of those ancient ideas then invade, permeate, and flavor (if you will) the vision of Narnia unique to that book. Each volume, then, corresponds to one of those planets and contains within it characteristics and impressions from those planetary ‘influences.’ Furthermore, within each the role of Aslan is particularly shaped so that he, as the Christ figure, is presented to us in such a way that he is enrobed in the ethos of the volume’s governing planet.

How does this architecture play out? Consider for a moment The Lion the Witch and the Wardrobe, which is probably the best known of the Narnia books. The governing planet for this volume is Jupiter, or Jove—king of planets, from whose name we derive the term “Joviality.” His influence on the book is manifold: primarily in that the climax of the story is the crowning of the four children on thrones in Cair Paravel—a kingly act for a book about the king of planets. But his influence is vaster than this. The arc of the story is about the end of winter and the arrival of spring—if you will, the death of Saturn (which is cold and wintry) and the arrival of Jove (which is spring-like and celebratory). With this exegetical key in hand, what was formerly one of the most out-of-place aspects of the story—that is, the arrival of Santa Claus bringing gifts—finally makes sense. Because, of course, we must remember that Father Christmas is a Jovial figure (in more ways than one), and that his arrival in the story symbolically typifies the struggle between Saturn/Winter and Jove/Spring.

It is possible that you may cry, “Coincidence!” But as Ward works through the seven books of Lewis’s Narnia stories, this inner architecture becomes clearer and clearer. The Voyage of the Dawn Treader is the book about Sol (the sun). The very story is a journey toward the sun, within it the characters drink water that enables them to look into the sun, and the highlight of the story is the ‘undragoning’ of Eustace—which we discover is a ‘solar’ activity because Apollo, god of the sun, is known as the dragon slayer. The Magician’s Nephew is the book of Venus, were Digory the boy must make a choice of love: will he choose the allure and power Queen Jadus, his love for his Mother, or his true love for Aslan (who, in that volume, represents true Venus, as generator of life)? Each volume is like this. And it is worth observing that Ward’s research does not substantively change the Narnia books; rather, it enhances them—much like discovering hidden passageways and rooms in a house you thought you knew.

Ward’s book is impressive, well researched, insightful, and compelling. It reflects a comprehensive study of Lewis’s life and work as it plays out in the Narnia books. This substructure that Ward has identified is undoubtedly there. Furthermore, I would venture to say that once you see it, you cannot un-see it. As a result, Planet Narnia is a worthwhile read for anyone who is passionate both about Narnia and Lewis. But here I offer a caution. If you are merely interested in Narnia, you may find Ward’s broader treatment of Lewis’s thought and life daunting. It is, after all, a rather exhaustive assessment. But if you are interested in Lewis’s work beyond the Narnia books, I think you will find in Ward’s volume a handy guide to the thinking behind the man who invented Narnia. The book isn’t perfect, of course. A few of Ward’s planetary discussions could have made clearer connections, and his theorizing about the occasion of the Narniad was unconvincing. But the overwhelming impression of the book is one of wonderful, ground-breaking scholarship into the thinking of C.S. Lewis.

I can appreciate a cathedral without studying medieval architecture, but the experience is surely enhanced when I do. In the same way, while knowledge of Lewis’s medieval, astrological architecture is unnecessary to the enjoyment of his Narnia books, knowing it only enhances the experience. Ward’s book serves such an illuminating purpose, and Planet Narnia is an invaluable guide to any lover of Lewis’s Narnia.