A ""parallel-universe"" story--but one of a richness and ingenuity that may well find an audience beyond the science-fiction genre. What to compare it With? Well, it is set in an imaginary city by the name of Malacia, which may remind you of Goldoni's Venice or Villon's Paris. The hero is a blithe young scamp of an actor, and the plot is a robust sequence of wenchings and roisterings from tavern to stable to palace. True, the Malacians claim descent from dinosaurs (""the ancestral animals"") rather than apes, and their beliefs seem to have evolved from Roman mythology into several strains of a magic-ridden Manichaeism rather than Christianity; but it doesn't cramp the Malacian style in bed or badinage. If Aldiss had left it at that, his Malacia would have been just rousing good fun. But he has chosen to set this ebullient story in an age ripe for change--something forbidden to Malacia from its foundation by the First Magician's Curse. Nothing, the Curse decreed, must change in the city, and the Supreme Council's brisk trade in midnight stabbings and disappearances keeps it that way. Yet a progressive faction has all sorts of innovations afoot--balloon warfare, daguerreotype tableaux--and carefree Perian de Chirolo's involvement with them ultimately summons up terrible powers that force him to look at himself, his art, and his city out of ""the only knowledge there is--knowledge that ages you."" It is a tribute to the sheer exuberance of Aldiss' invention that his considerable freight of thematic baggage doesn't simply collapse under its own weight. A provocative, remarkably successful marriage of breezy jeu d'esprit and historical reflection.