HOW, precisely, do some heroes leap into children's hearts, while others languish in the outer, adult darkness? Harry Potter, boy wizard, has zipped faster than a speeding broomstick into the affections of young readers.

His first appearance, and happy bound into the first rank of literary stardom, have been well documented. Harry Potter And The Philosopher's Stone, JK Rowling's debut, last year attracted dizzying praise and advances, won the Smarties Award and caused very large numbers of children indeed to adopt an esoteric vocabulary of Muggles and Hufflepuffs. Playgrounds resound to the sound of Quidditch - an airborne wizardly game featuring some very snazzy aerobatics. Children play at Harry Potter: the ultimate compliment.

This, the much-anticipated sequel - there will be seven in all - is already selling in silly numbers and scarcely in the shops yet. In the first book, we learned that Harry Potter is very far from an ordinary boy, despite his cheery, apparent normality. A lightning mark on his forehead reveals his identity and destiny.

The dark and evil Lord Voldemort killed Harry's parents when he was still a baby; but all his darkness failed against the boy. Hence, Harry Potter is a legendary name in the world of wizards and witches - a parallel universe which Rowling creates with immense wit and inventiveness alongside the dullard world of the Muggles, or non-magical folk.

That same contrast, the ghastly suburbia of Harry's aunt and uncle and truly revolting cousin Dudley set against the gorgeous, chaotic scariness of the magical world, also illuminates this second book.

Dudley's world is one of business deals and boringness. Harry's world, once he has escaped, is one where cars can fly, where pixies can run amok in a classroom, where mandrake roots reveal themselves as ugly squealing babies as they are tenderly replanted.

This is the world of Hog- warts' School of Witchcraft and Wizardry, the boarding establishment where lessons are in wand use and potion-making rather than algebra and English, where peevish ghosts wander the corridors and personal owls deliver the post.

In this instalment of the life of Harry, strange attacks on the student wizards indicate that the fabled chamber of secrets has been opened; and there will be fine, funny and terrifying adventures with snakes, spiders and some very bad baddies indeed before modest, brave, determined, slightly bamboozled Harry wins through.

It might all be thought to be endearingly old-fashioned. These kids may say "cool" and compare latest makes of broomstick as if they were the trendiest trainers.

The setting, however, Hogwarts School, is Enid Blyton meets Mervyn Peake - a sort of jolly japes in Gormenghast. These books are not particularly contemporary, they are not particularly topical, the Spice Girls feature nowhere within them, they are not on the television (yet - they cry out for small and large screens to seize their fabulously visual characters and settings); and children love them, passionately and hungrily.

Let us ponder, then, Harry Potter and what children actually want from books. It's clear that they don't want didacticism or dullness; they don't want to be pandered to or patronised. They do want some or all of the following: a rich, complete and exciting world in which to immerse themselves; heaps of magic for the days when yet more books about dating or football begin to pall; a brilliant storyline, hooking and holding fast; plenty of jokes and twists and turns and a bit of rudeness and a bit of goodness.

For, even if they absolutely don't want moralising, they do want a large and generous sense of the moral. Rules may be broken, people may do daft, bad things, but children need to know that they too have the courage and wit and bigness of heart to ward off adversity. In the only line even remotely resembling a message here, Albus Dumbledore, great wizard and head of Hogwarts, says to Harry who has been fretting about his own potential to be a dark, rather than good, wizard: "It is our choices, Harry, that truly show what we are, far more than our abilities."

Harry is special, and Everychild too. Those who have yet to meet him should make his acquaintance now.

The sheer buoyant zest of Joanne Rowling's storytelling should seduce even the sternest Muggles.

• A Harry Potter fan club will be launched on 2 July. You will be required to state which wand hand you use, which Quidditch position you play in and which magical creatures you own. More information from: Harry Potter Fan Club, Bloomsbury Publishing plc, 38 Soho Square, London W1V 5DF.
• JK Rowling will be reading on 2 July in Waterstones, Sauchiehall Street, Glasgow, at 11am; and in Dillons, St Vincent Street, Glasgow, at 3pm. On 3 July she will be in Edinburgh, in Waterstone's West End at 7pm. She will also be appearing at the Edinburgh Book Festival in August.

Copyright 1998 The Scotsman Publications Ltd.