Rowling's greatest trick is not magic but momentum, although her sentences occasionally need a little help keeping up.

Harry Potter and the Sorcerer's Stone is a fantasy novel built around an enviably durable premise: an abused, neglected boy discovers that he is a wizard and is whisked away to Hogwarts, where friendship, rivalry and a rather dangerous mystery await him. The machinery is familiar now, but the first book's real pleasure lies in the briskness with which Rowling assembles her world.

Her prose is straightforward, highly legible and unapologetically functional. Critics have disagreed sharply about its literary polish. The New Yorker's assessment is more generous, noting Rowling's lack of sentimentality and her ability to achieve emotional effects through small social gestures. Charles de Lint similarly praised her grasp of character, caricature and humour, particularly her ability to write for children without condescending to them.

The harsher verdicts are not without merit. The Guardian's Nicholas Lezard attacked Rowling's prose as flat and pedestrian, particularly objecting to her reliance on adverbs and familiar descriptive habits. More recently, Katherine Rundell made much the same complaint from a more sympathetic position, observing that the prose sprawls and is heavily populated by adverbs and adjectives. The criticism is easiest to understand when one notices how often Rowling tells us precisely how a character speaks or feels instead of allowing the surrounding action to establish it. The writing is rarely subtle when it can be explicit.

Yet calling the prose merely clumsy misses something important. It is exceptionally well suited to narrative velocity. Scenes are short, information is introduced with purpose, and apparently incidental details are often planted with remarkable foresight. Reactor's appreciation of the novel makes much of this efficiency, noting how seemingly casual details acquire significance later in the series. Rowling writes less like a stylist polishing individual sentences and more like an architect laying track several chapters ahead.

And here, finally, I will permit myself one unguarded admission: the imagination is magnificent. Hogwarts feels inviting because Rowling understands that a fantasy world becomes convincing through accumulated particulars, not grand declarations. Chocolate frogs, moving staircases, ridiculous school rituals and dangerous forests do more work than pages of mythology ever could.

The prose is not elegant. Sometimes it is positively ungainly. But it knows exactly where it is going, and it gets there quickly.

Verdict: an uneven stylistic performance rescued, and then some, by extraordinary narrative instinct.