Like millions of people throughout the world, I spent most of Saturday curled up in a chair, racing through the latest, and last, Harry Potter novel, not only because of the breakneck pace of the story but because my 17-year-old son was due home on Sunday and there would be dire consequences if I didn't hand over the book immediately.
Six enchanted hours after beginning, I re-emerged, exhilarated, both as a reader and a writer. She had done it. She had pulled off an intensely satisfying end to what has been the most extraordinary literary success story of our time.
From the sprightly, astonishingly assured Dickensian beginning of the first in the series (which, remember, was her first novel), to the fairytale closure of the last, the Harry Potter series shows the mark of a true genius of children's literature whose work I confidently predict will endure.
Genius? Can that be right? J.K. Rowling's astonishing success over the Potter decade (and for people of my 17 and 20-year-old sons' generation, worldwide, it is probably the strongest cultural marker and link of all) has not only brought her legions of fans but small armies of detractors.
There are religious literalists, getting hold of the wrong end of the stick as usual, missing the deep Christian resonances and characterising the Harry Potter books as demonic, much as in the 1960s when similarly blinkered literalists wanted to ban C.S. Lewis's The Chronicles of Narnia on the grounds it was "too pagan".
There are also sundry literary high priests, such as Harold Bloom, who have slammed the series for being a sign of "cultural infantilism".
Then there's the kind of evaluation in which Rowling's artistic achievement is routinely denigrated and her success explained away by saying things like The Australian's critic Peter Craven did, that the books "appealed to the lowest common denominator", as if Rowling was the purveyor of some kind of McBook.
Rowling's work is sometimes unfavourably compared to the books of other great fantasy authors, such as Lewis, J.R.R. Tolkien and Philip Pullman, and the quality of her prose and artistic vision questioned. Often critics appear not to have read the works but rely on the sanctification of time or literary awards to persuade them that Rowling's work is inferior to the others'. But I've read all the authors in question, and I disagree.
All of these books share the great themes of good and evil and the quest for wisdom and love. Their authors also share a strong background in classical literature, myth and fairytale. They are all great storytellers. Rowling shares with Tolkien a glorious gift for what the old ringmaster called "the art of subcreation, the power to give fantasy the inner consistency of reality" and also a good eye for a satisfying ending, but thank heavens she doesn't share with him a taste for tedious genealogies, over-solemnity or ghastly dwarf songs.
She shares with Lewis a spring-like freshness, sense of fun, broad satire and a marvellous inventiveness but, unlike him, she finished her series well: the final book in the Narnia series, The Last Battle, was a bitter disappointment to me as a child as it's far too polemical and theme-driven. This is also true of Pullman's much-admired His Dark Materials, which begins magnificently with Northern Lights, starts to falter in The Subtle Knife and falls in a heap in The Amber Spyglass which, mirroring the final book in the series of his bête noire, Lewis, fails to trust its characters and story and descends into preaching (of the opposite viewpoint). With Pullman, however, Rowling shares a happy talent for names, and terrific pace and timing.
As to the quality of her prose, I reckon Rowling pretty much matches Lewis: engaging, bright and child-oriented, with a great clarity and playfulness of expression, mixed with some clunky bits and some clichéd moments. (Pullman and Tolkien are perhaps more consistent, more adult-oriented prose stylists, though they too have their flaws.) Her characters are archetypal but so are all the others': fantasy thrives on the archetypes which live deep in all of us.
Rather than appealing to "the lowest common denominator", the Harry Potter books, like the great fantasy novels, fairytales and myths, appeal to the deepest common denominator. Yet Rowling also allows for a good deal of ambiguity and contradiction in her characters, even in what I call the Dark Lord test.
We get a real sense of the pitifulness as well as the evil of Voldemort, something that isn't true of Tolkien's Sauron or Lewis's White Witch, while in Pullman's trilogy those associated with the tyrannical church are often caricatures of evil.
And so it is Rowling who emerges, in the end, as the most sophisticated of them all, her magpie mix of gifts at the very heart of her genius.