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 love, choice, and the implications, large and small, of whom we choose to love. 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. With which true love is Irina better off? Should she stay or should she go? In two alternating, parallel stories, The Post-Birthday World follows Irina's life as it unfolds under the influence of these two drastically different yet equally honorable men. Poignant and deeply honest, written with the subtlety and wit that are the hallmarks of Shriver's work, this enchanting work of fiction appeals to the what-if in us all.