I defy anyone not to fall in love with Sister Mariana de Alcoforado, an aristocratic girl sent to the convent at Beja in Southern Portugal because her elder sister married first. Mariana is still famous in Portugal - as she was throughout Europe in the seventeenth century - for the beautiful, astonishingly frank love letters she sent the French officer who abandoned her after a brief but all-consuming affair. While the letters, in a new translation by Vaz, appear at the centre of the novel and the effects of the affair resonate throughout Mariana's life, the book and Mariana are much grander and more powerful than a simple love story. The book deftly sets the true story of a nun's passion into the richly imagined details of the rest of her life, all against the background of Portugal's desperate struggle to free itself from Spanish rule.

Vaz's imagination and the extraordinary mixture of believable reality and wild spirituality match the best of Isabel Allende. Like Allende she leads us tenderly but mercilessly from scenes of delicious humour - the resurrection of drunken plucked geese, to wrenching courage - the old nun who goes blind playing her beloved organ all night during the plague. Throughout, the character of Mariana is indomitable, grabbing at joy, pain and love with arms wide open, as she inspires and enriches the lives of all those who come into contact with her, including this reader.