Iain Pears's latest novel consists of three separate narratives, all set in and around the little Provence town of Vaison. In the fifth century, as the Roman Empire is overrun by Barbarians, Manlius Hippomanes, Bishop of Vaison, tries to save Provence from the Visigoths; in the 14th century, as Europe is ravaged by the Black Death, the central figure is a Provençal poet, Olivier de Noyen; and in the 20th century it is Julien Barneuve, an academic working on Olivier who becomes a censor for the Vichy government.

The stories are connected by a neo-Platonic treatise, The Dream of Scipio, composed by Manlius, discovered by Olivier and rediscovered by Julien.

The fates of the characters, too, are similar: each is desperately in love - each, confronted by a moral dilemma, must take a stand on the persecution of the Jews and each discovers, in Manlius's words, that "the evil done by men of good will is the worst of all". Though Pears, switching backwards and forwards through the centuries, interweaves the stories with extraordinary skill, The Dream of Scipio lacks the obvious appeal and rich homogeneity of An Instance of the Fingerpost, the author's previous novel, set in Restoration Oxford.

It initially seems dry, philosophically abstract, and artificially schematic in its linking of the three narratives. But the breadth of reference, the fluent and convincing recreation of three very different milieux are impressive. And, gradually, as Manlius turns from man of thought to man of action, as Olivier's love expresses itself in a burst of lyric genius and as Julien finds momentary happiness with the Jewish artist Julia Bronsen, the novel gains in power and weight, irresistibly seizes the imagination and ends in almost unbearable tragedy.