In this eagerly awaited new novel, Lionel Shriver, the Orange Prize-winning author of the international bestseller We Need to Talk About Kevin, delivers an imaginative and entertaining look at the implications, large and small, of whom we choose to love. Using a playful parallel-universe structure, The Post-Birthday World follows one woman's future as it unfolds under the influence of two drastically different men.

Children's book illustrator Irina McGovern enjoys a quiet and settled life in London with her partner, fellow American expatriate Lawrence Trainer, a smart, loyal, disciplined intellectual at a prestigious think tank. To their small circle of friends, their relationship is rock solid. Until the night Irina unaccountably finds herself dying to kiss another man: their old friend from South London, the stylish, extravagant, passionate top-ranking snooker player Ramsey Acton. The decision to give in to temptation will have consequences for her career, her relationships with family and friends, and perhaps most importantly the texture of her daily life.

Hinging on a single kiss, this enchanting work of fiction depicts Irina's alternating futures with two men temperamentally worlds apart yet equally honorable. With which true love Irina is better off is neither obvious nor easy to determine, but Shriver's exploration of the two destinies is memorable and gripping. Poignant and deeply honest, written with the subtlety and wit that are the hallmarks of Shriver's work, The Post-Birthday World appeals to the what-if in us all.

• 2007fiction