"Harry Potter" pundit John Granger additionally noted that one of the reasons the "Harry Potter" books were so popular is their use of literary alchemy (similar to "Romeo and Juliet", C. S. Lewis's "Perelandra" and Charles Dickens's "A Tale of Two Cities") and vision symbolism. In this model, authors weave allegorical tales along the alchemical magnum opus. Since the medieval period, alchemical allegory has mirrored the passion, death and resurrection of Christ. While the entire series utilises symbols common in alchemy, the "Deathly Hallows" completes this cycle, tying themes of death, rebirth, and the Resurrection Stone to the principal motif of alchemical allegory, and topics presented in the first book of the series.