Celia Brayfield's Heartswap follows on from her earlier successes--Pearls, Harvest, Getting Home and Sunset--and returns to familiar territory: the perennial battles and misunderstandings between the 21st century sexes. The novel begins with transatlantic e-mails between two old friends discussing their impending marriages, Flora to Dillon, "Financial products design. 6ft 2in. Buns of custard", and Georgie to Felix, a medical researcher investigating the mysteries of "Lightoller's Syndrome". All seems well until their glacial, glamorous former boss Donna suggests that they try to seduce each other's man as a trial of their fidelity and commitment. Against Flora and Georgie's better instincts both find themselves playing the game. To their relief, they find that their initial attempts at seduction are rebuffed but then as Heartswap is at pains to insist, men are never as simple nor as reliable as that. The prose is sometimes lacking in wit and humour, the "guys" are rather stereotypical and the story spirals into increasingly black and rather unexpected territory. However, Brayfield's novel is still a well-observed and acerbic comedy of manners between the sexes in "the economic acropolis of London" at the beginning of the new millennium. --Lucy Snowe