Over twenty years ago, Umberto Eco artfully invented a mass-selling genre for the novel with The Name of the Rose, his postmodernist pastiche romp through medieval murder and theology. Since then, he has written novels at regular if leisurely intervals of around eight years, amid a busy career as star of the international academic lecture circuit, cultural commentator, and author of serious volumes on semiotics and aesthetics. The later novels have sold remarkably well, but they have never quite reached the peak of crossover success, in both sales and estime, achieved by the first. In Foucault's Pendulum, he wove a mystery tale out of a fabulous compendium of secret societies and conspiracies from the Rosicrucians to the Protocols of the Elders of Zion. Then came The Island of the Day Before, a more lyrical (and more turgid) narrative, about time, navigation and the mysteries of longitude (Eco got there before Dava Sobel, but she had the lighter touch and the neater story to tell). Now, with his fourth novel, Baudolino (already a runaway hit in much of mainland Europe), we are back with the marauding confusions of the European Middle Ages – back, that is, to some of the ingredients brewed up to such winning effect in The Name of the Rose.

Baudolino is a young scallywag with a gift for fakery and for languages, growing up in the late twelfth century in the murky marshlands of lower Piedmont, where the city of Alessandria now stands (indeed, we see its troubled foundation later in the novel). There he stumbles across a fearsome