The author: Terry Pratchett, 50 next year, Berks-bred retired reporter and former press spin-doctor for three CEGB nuclear power plants; now possibly the highest-earning - and probably the best-loved -- British writer.

The book: Jingo (Gollancz, pounds 16.99), number 21 in the inconceivably successful Discworld series of comic fantasies that began in 1983. As its title more than hints, the whiffy old metropolis of Ankh-Morpork edges towards a showdown with the Islamic-sounding state of Klatch. As carnage looms, the City Watch misbehave as ever and dear old capitalised Death - cherished by all Pratchett junkies - TURNS IN HIS USUAL CAMEO ROLE.

The deal: The Discworld list shifts a million copies a year; even new hardbacks quickly break the 100,000 barrier. In a Beatles-style feat, Pratchett has headed hardback and paperback charts simultaneously three times. Remember that his cult thrives not just with every teenage Kevin but with Kevin's mum as well (since Woman's Hour serialised the Discworld debut). You can buy Discworld figurines, attend conventions, play computer games - but disputes have delayed the movie.

The goods: Pratchett fixed the Discworld formula from the off - a JRR Tolkien world rendered in PG Wodehouse prose - and he's had no cause to change the mixture since. But the targets of his liberal satire shift with every volume. Jingo squares up to military idiocy in all its uniforms, from the arms trade (fancy a "Great Leveller" Cart-Mounted Ten-Bank 500- Pound Crossbow?) to the urge to demonise foes ("It was so much easier to blame it on Them. It was bleakly depressing to think that Them were Us.") It also mocks - in lightly coded form - both sides of the paranoid divide between Islam and Europe. As for Death, he stops the show, as always. ("`No more dandruff?' said Snowy... EVER, said Death. TRUST ME ON THIS.")

The verdict: Thirty years ago, teachers used to fret about the kids who only read Tolkien. Now those pupils' own children may confine print excursions to the Discworld. That's progress. Given the occult claptrap espoused by so many youngsters' favourites, it's a slice of luck that Nineties adolescents have fallen into the hands of such a decent, sturdy liberal. Besides, for the pace and precision of his comic dialogue, Pratchett's still without a peer this side of Blandings Castle.