'You can leave a forest, but you can never leave a cloister; you are free in the forest, but you are a slave in the cloister.'Diderot's The Nun (La Religieuse) is the seemingly true story of a young girl forced by her parents to enter a convent and take holy orders. A novel mingling mysticism, madness, sadistic cruelty and nascent sexuality, it gives a scathing insight into the effects of force...