For over half a century, scholars have labored to show that C. S. Lewis's famed but apparently disorganized Chronicles of Narnia have an underlying symbolic coherence, pointing to such possible unifying themes as the seven sacraments, the seven deadly sins, and the seven books of Spenser's Faerie Queene. None of these explanations has won general acceptance and the structure of Narnia's symbolism has remained a mystery. Michael Ward has finally...