Books: In search of a life less ordinary - and more risky

Would you like to take a holiday from yourself? Mary Allen enjoys a couple of chilling trips across the frontiers of personality

Mapping the Edge

by Sarah Dunant

Virago, pounds 10.99, 332pp

Taking Lives

by Michael Pye

Phoenix House, pounds 9.99, 384pp

BOTH SARAH Dunant and Michael Pye examine themes of identity in their latest novels, looking at what happens when the constraints we take for granted - whether imposed by circumstances, relationships or our past - are removed to create what Dunant describes as "stories from the edge". When Anna, the central character in , fails to return from a brief and unexplained trip to Italy, her friends Estella and Paul begin to create fantasies about why she went and what might have happened to her. Both fear she might be dead, and their imaginations start to fill the void. As their anxieties grow, so does the relationship between Estella and Lily, Anna's six-year-old daughter, with Estella being driven back through her past to re-examine the death of her own mother and how she dealt with the subsequent pain.

Anna's experiences in Italy develop in two parallel scenarios, in which Anna alternates between being a kidnap victim and the willing collaborator in an adulterous affair. It is unclear whether these are her fantasies, or whether they are being created by those she has left behind. They could be two stories selected from a potentially infinite number, in all of which Anna would be forced to face a version of her fears and decide whether she is going to rule or be ruled by them.

Part of what makes so compulsive to read is that it functions with real confidence and assurance on several levels. Two thrillers are interwoven with the gradually accumulating tension of those left behind, arousing complementary anxieties and exploring the darkness at the heart of Dunant's characters. The formal structure of the novel gives a ritualistic sense to the action, as though - like a game - it is contained within a set of boundaries within which the more frightening aspects of the imagination can be explored. Dunant does not try to find easy answers, nor does she go for a tidy resolution: there is a sense of the novel continuing even though the characters might have left it.

Martin Arkenhout, in Taking Lives, has no problem in crossing the boundary between his and others' lives. He finds men who have a passport, good credit, no commitments and few connections - and kills them, assuming their identities until boredom or necessity requires him to move on. Eventually, he misjudges his victim, taking the life of someone with all too many connections, notably with the museum from which he has stolen paintings.

John Costa, sent by the museum to catch the thief, is experiencing the dissolution of his own life as his marriage breaks down and the burial of his father reveals an unexpected past. Once the two men come face to face, their struggle gradually becomes a question of which of their identities will survive.

For most of the book the plot is carried forward convincingly, but as the action moves towards its conclusion the choices facing the characters begin to feel slightly contrived. That apart, this is a well- constructed thriller, inspired by a real-life criminal who, the blurb notes, "is still at large".