In the middle of the 19th century, Europe's fascination with Egypt was at its zenith. Wellheeled young travellers set out for Cairo and Karnak with all the excitement of modern school-leavers jetting off to Goa and Machu Picchu. Then, as now, travel was supposed to broaden the mind, transform the spirit and rejuvenate the tired old souls of the bourgeoisie.

Anthony Sattin's book takes place in the winter of 1849, when an unhappy Englishwoman and an obscure French writer boarded the same boat leaving Alexandria for Cairo. Florence Nightingale and Gustave Flaubert were never introduced, during the voyage or afterwards, but Sattin weaves their accounts of Egypt into an enjoyable parallel micro-biography: the story of a single winter that changed both their lives.

Each hoped the trip up the Nile would bring the answer to a dilemma. Flaubert had just written a draft of The Temptation of Saint Anthony, which his most trusted literary friends had told him was only fit for burning, while Nightingale had failed to persuade her parents to let her become a nurse. Both wrote prolifically while in Egypt, though neither is quite the writer one expects. Nightingale's diaries, with their eager interest in landscape and local colour, nicely complement Flaubert's more self-absorbed jottings about dancing girls and his own dreams of literary success.

Sattin has previously edited a collection of Nightingale's letters home from Egypt, and is perhaps more comfortable writing about her transformative voyage than about Flaubert's dissolute gap year. Florence wanders awestruck in temples, conjuring up the land of the Pharaohs and hearing the voice of God calling her to a life of service. Gustave prefers vegetating on the deck of his sailboat and occasionally making the most of Egypt's burgeoning market in sex tourism. But the two become unwitting companions and lively guides to Victorian Egypt. And while Sattin is a little coy about the fleshpots of Cairo  Flaubert's self-confessed homosexual encounters are oddly glossed over  his careful shadowing of the famous tourists makes an unconventional biographical diptych out of a tantalising historical coincidence.