'Metaphysical thriller', a recent coinage, threatens to become a tediously overused term in describing recent novels; and yet for works such as this, for Martin Amis's Other People, for Peter Ackroyd's Hawksmoor, it serves well enough. In Ticket to Ride, Potter continually manipulates and disappoints our expectations, and where the conventional thriller does this through skilful prestidigitation of all the naturalistic data, this novel meddles with more fundamental empirical evidence, denying the reader even the security of a consistent narrator. Henry James would have accused such writers of cheating, for Potter is less concerned with the figure in the carpet than with pulling out the rug from under us. Indeed the desire to shock may occasionally overwean Potter - it is perhaps too easy to point to the exigencies of television writing here - but overall such impulses make for a tauter, climactic piece.

Ticket to Ride is compulsive reading and its pleasures are seldom superficial: the fractured narrative reflects a deeper disjointure. Potter's obsession with psychology - both Freudian and popular - leads him to consider the thoughts of an amnesiac who fears recovering his memory and tries to shore up his neatly circumscribed present ruin with what fragments of his past he cannot suppress. But what begins as an exploration of one mind in fugue reveals gradually an incipient, subconscious folie à deux which intrudes upon, alternates with, and finally threatens to supplant a more conventional relationship. In a subtle Freudian inversion John and John, ...