The Chrestomanci books deal with a number of parallel worlds where magic functions to a lesser or greater extent. The world of Witch Week is much like our own, but it is also a world where witches exist and are persecuted by an inquisition and burned. Unlike the closet mage society of Harry Potter, which is firmly entrenched in this world, the world of Witch Week is explicitly defined as a mirror of our own. For that reason it is much more "fantasy" that "magical realism".
One thing that many fantasy authors fail to realise is that magic is not a plot element in itself. When the bulk of the average "speculative" reader's intake contains fantastic elements, the very nature of magic ceases to become an esoteric quantity to the reader, no matter how secret the magical society is in the book - and simply by demonstrating the power of the mage, throwing fireballs and turning people into toads, the author is hardly embelishing the story. Magic may be a thing of wonder for the characters but for readers of fantasy it is an old and stale concept, and should be regarded as a vehicle for plot and character progression, not an end unto itself.
Diana Wynne Jones exceeds my already high expectations with her superb book. Although magic is outlawed and feared in this world, as it is ignored in Potter, the setting has more in keeping with The Worst Witch - magic is an exoteric quantity in this world that acts as a common denomenator. The fact that witches in this world can do fantastic things is neither here nor there, because both the reader and the characters are familiar with magic. As such it is a literary tool, and a metaphor - Jones uses the concept of magic to highlight the cruelty of a society, especially in the youth population, that regards any difference as threatening. Had Jones written about a white elitist society where half-caste children are persecuted, the end result would have been darker and more politically relavent but no less poignant. Her portrayal of the individual characters is vivid and realistic, and the bullying of the different characters and the responses to their torment are believable. More to the point, Jones gives an insightful analysis of heirarchies within child groups. This particularly struck a chord with me, and far exceeds the ham-fisted and dry efforts of J K Rowling.
When it is used, the magic shows imagination and the sort of application one might expect from a schoolboy. Not only that, it is woven into the storyline perfectly. Towards the end, the metaphysic of the plot does not disappoint, and Jones achieves an excellent closure, showing an attention to tight plotting that is rare in any fiction. Whilst the whole lacks the sophistication of Northern Lights, it has no pretentions to such grandeur - this is a story that uses its elements in a subtle yet functional way to produce an adventure that is as touching as it is exciting. Excellent.
