BOOK REVIEW / No mere digestive tract: 'Millroy the Magician' - Paul Theroux: Hamish Hamilton, 15.99 pounds

'GOODBYE, America,' declaims Allie Fox, the tyrannical crackpot genius of an inventor in Paul Theroux's 1981 novel The Mosquito Coast, at the start of his sea-voyage to Central America. 'Goodbye to your junk and your old hideola] And have a nice day]'

Fox dreams of making his fortune by building a gigantic ice-making plant in the heart of the Honduran jungles (a dream that reminds one of Melquiades the gypsy bringing ice - 'the largest diamond in the world' and 'the great invention of our time' - to Macondo in Garca Marquez's One Hundred Years of Solitude). The wild energy with which Fox drags his family towards catastrophe infects the writing and makes the novel, along with the more recent and perhaps even better My Secret History, this prolific author's most successful fiction to date.

Now Theroux has deliberately set out to write a companion-volume to The Mosquito Coast. The eponymous hero of Millroy the Magician (conjurer, wizard and founder of a nationwide food cult) is, like Fox, several times as large as life, and, again like Fox, both in love with America and in revolt against its junk and old hideola. But whereas Fox flees his homeland in the hope of creating a brave new world, Millroy has no interest in 'overseas'. His mission is the cleansing of America itself; or, to be more precise, the cleansing of America's innards.

Using the Bible as his only recipe book, refusing to eat anything with a face or a mother, Millroy preaches a hot gospel of roots and grains; the televangelist of roughage - at the height of his television celebrity he is nicknamed 'Anal Roberts' - it is his goal to make every American expel two pounds of waste matter a day. And, in contrast to his alter ego Allie Fox, he is implacably opposed to what he sees as the spurious preservative magic of ice.

Weird, huh. But Millroy the Magician is no mere digestive tract. Beginning in a fairground and ending with a manhunt, it bites off as much of American society, and American literature, as it can chew. Behind the flamboyant figure of Millroy we are asked to see not only Oral Roberts, Jim Bakker and Billy Graham but also Elmer Gantry and the wise-bloody fervour of Flannery O'Connor's holy fools. And there are echoes of Huck Finn and Tom Sawyer, too: because Millroy is surrounded by children - the wonderfully named urchins of Barnstable County (Lynette Trumpka, Zula Firkins) in his magician incarnation, and, later, the mostly black kids (T Van, Dedrick, Daylon, Peaches) who dance to his foodist tune, rejoicing in the odorous felicities of toilet language; and because a childlike lushness of dialect and colloquialism, from Massachusetts to Hawaii, is the novel's greatest strength. Millroy bewitches the children and makes them his disciples (the book constantly challenges our definitions of the borderline between charm and corruption). But he is no Pied Piper, and in the end it is his devotees who will drag him down.

Like The Mosquito Coast, the novel is seen through a youngster's eyes. Here it is Jilly Farina, fourteenish when the novel starts, sixteenish when it ends, even her surname a tribute to grains. Millroy sees her at a fair, spirits her away from her savage white-trash folks, makes her pretend to be a boy, tells her she is the secret of his power, lures her towards the heart of his magic and mystery. We wonder when this is going to become a book about sexual perversion, when Humbert will burst out of Millroy, when Jilly aka Alex aka Rusty will reveal herself as Lolita; and it doesn't happen, and she runs away, then back, she is mesmerised and afraid and knows he is messing with her head, but on the other hand without him she is nothing. They journey from the television success of a show called Paradise Park to the real-life paradise of Hawaii - and here, finally, it is suggested that we may have been reading not some sort of mealtime Lolita but a transatlantic reworking of The Tempest, the tale of an American Prospero and his Ariel. Or a love story, in which love makes the strong weak and the weak capable of sorcery.

As an allegory, this fictional tirade against America the Gluttonous on occasion goes on too long, on occasion strains a little too hard. When Millroy - who is a fundamentalist of sorts - attacks Sesame Street for its multi-culturalist secularism, you wonder if this tale of competing television shows is not too fragile to be turned into a war between the Sacred and the Profane. And since the food Millroy loves sounds so chewily, stringily, ponderously awful, you can't help feeling no self-respecting kids would really have gone for it, no matter how revoltingly enjoyable Millroy's tricks with stomach pumps might be.

These are only quibbles, however. Millroy the Magician is a hugely ambitious, capacious fiction that manages to be at once entertaining and unsettling. And as for the magic - the people turned into drinks and gulped down, the melting rats, the chopped-up fingers, the storms that engulf airplanes, the raising of the dead - well, jeekers, as Jilly Farina would say, it's wicked scary.

(Photograph omitted)