In writing this second book Lewis had mused about what it would be like for the genii who is summoned - drawn from his own world to do the bidding of the holder of the lamp. From this kernel of an idea he created a memorable and gripping sequel to his first adventure in Narnia.
Lewis tells the story, seamlessly using different points of view, introducing new and old characters, drawing the threads together at the right time, letting the title character grow and develop along with the story. The technique isn't uncommon but it is rarely done so well. A masterclass.